Abakcus https://abakcus.com Math, science, education, and design: videos, tools, books, articles, lists, and gadgets — hand-picked, one calm place. en-us Wed, 11 Nov 2026 00:00:00 GMT How to Make Ice Cream in a Bag With Ice and Salt https://abakcus.com/diy/how-to-make-ice-cream-in-a-bag https://abakcus.com/diy/how-to-make-ice-cream-in-a-bag Milk, sugar and vanilla in one bag; ice and salt in another. Ten minutes of shaking makes real ice cream, colder than a freezer can get.

Milk, sugar and vanilla in one bag; ice and salt in another. Ten minutes of shaking makes real ice cream, colder than a freezer can get.

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]]> Wed, 11 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Pizza Box Solar Oven That Really Cooks https://abakcus.com/diy/how-to-make-a-pizza-box-solar-oven https://abakcus.com/diy/how-to-make-a-pizza-box-solar-oven An empty pizza box, some foil, black paper and cling film. Point it at the Sun and in half an hour the chocolate melts and the marshmallows go gooey.

An empty pizza box, some foil, black paper and cling film. Point it at the Sun and in half an hour the chocolate melts and the marshmallows go gooey.

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]]> Wed, 11 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a String Telephone From Paper Cups https://abakcus.com/diy/how-to-make-a-string-telephone https://abakcus.com/diy/how-to-make-a-string-telephone Two cups, a long string and a friend at the far end of the garden. Whisper into one cup and your voice arrives at the other, carried by a shaking thread.

Two cups, a long string and a friend at the far end of the garden. Whisper into one cup and your voice arrives at the other, carried by a shaking thread.

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]]> Wed, 11 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) 1/2 + 1/4 + 1/8 + … = 1: A Proof Without Words https://abakcus.com/articles/geometric-series-proof-without-words https://abakcus.com/articles/geometric-series-proof-without-words Cut a square in half, then cut what is left in half, and keep going. The pieces never run out, yet together they make exactly one square.

Cut a square in half, then cut what is left in half, and keep going. The pieces never run out, yet together they make exactly one square.

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]]> Wed, 11 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) The Binomial Cube: A Proof Without Words for (a + b)³ https://abakcus.com/articles/binomial-cube https://abakcus.com/articles/binomial-cube Three cuts through a cube turn (a + b)³ into eight blocks you can count: one, three, three, one. A proof you read with your eyes.

Three cuts through a cube turn (a + b)³ into eight blocks you can count: one, three, three, one. A proof you read with your eyes.

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]]> Wed, 11 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Balloon Hovercraft From an Old CD https://abakcus.com/diy/how-to-make-a-balloon-hovercraft https://abakcus.com/diy/how-to-make-a-balloon-hovercraft An old CD, a bottle cap and a balloon. Open the cap and the disc lifts a hair’s breadth off the table, then glides away at the faintest touch.

An old CD, a bottle cap and a balloon. Open the cap and the disc lifts a hair’s breadth off the table, then glides away at the faintest touch.

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]]> Tue, 10 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Spectroscope From a CD and a Cereal Box https://abakcus.com/diy/how-to-make-a-cd-spectroscope https://abakcus.com/diy/how-to-make-a-cd-spectroscope An old CD and a cereal box make a real scientific instrument. Point it at the sky, a lamp or a street light and see the hidden colours each one is made of.

An old CD and a cereal box make a real scientific instrument. Point it at the sky, a lamp or a street light and see the hidden colours each one is made of.

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]]> Tue, 10 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Tangram From a Square of Card https://abakcus.com/diy/how-to-make-a-tangram https://abakcus.com/diy/how-to-make-a-tangram One square of card, five straight lines, seven pieces. Rearrange them into cats, boats and swans, and every picture has exactly the area of the square.

One square of card, five straight lines, seven pieces. Rearrange them into cats, boats and swans, and every picture has exactly the area of the square.

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]]> Tue, 10 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make Straw Pan Pipes That Play a Real Scale https://abakcus.com/diy/how-to-make-straw-panpipes https://abakcus.com/diy/how-to-make-straw-panpipes Eight straws, a ruler and a lump of clay. Cut them to length, seal the bottoms and blow: a whole octave, tuned by nothing but the speed of sound.

Eight straws, a ruler and a lump of clay. Cut them to length, seal the bottoms and blow: a whole octave, tuned by nothing but the speed of sound.

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]]> Mon, 09 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make Reuleaux Triangle Rollers That Roll Like Circles https://abakcus.com/diy/how-to-make-reuleaux-triangle-rollers https://abakcus.com/diy/how-to-make-reuleaux-triangle-rollers Three curved triangles cut from card, and a book that glides across them as smoothly as on round rollers. Not every shape that rolls is a circle.

Three curved triangles cut from card, and a book that glides across them as smoothly as on round rollers. Not every shape that rolls is a circle.

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]]> Mon, 09 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Sundial From a Paper Plate https://abakcus.com/diy/how-to-make-a-sundial https://abakcus.com/diy/how-to-make-a-sundial A paper plate, a pencil and the turning Earth. Tilt the plate to your latitude, point the pencil at the pole star, and the shadow turns 15° every hour.

A paper plate, a pencil and the turning Earth. Tilt the plate to your latitude, point the pencil at the pole star, and the shadow turns 15° every hour.

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]]> Mon, 09 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) Free Math Courses on Coursera: The 26 Worth Taking https://abakcus.com/articles/free-math-courses-coursera https://abakcus.com/articles/free-math-courses-coursera Twenty-six Coursera math courses from Stanford, Penn, Imperial and Johns Hopkins, sorted into a curriculum, with what free really means on Coursera now.

Twenty-six Coursera math courses from Stanford, Penn, Imperial and Johns Hopkins, sorted into a curriculum, with what free really means on Coursera now.

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]]> Mon, 09 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Kaleidoscope From a Kitchen-Roll Tube https://abakcus.com/diy/how-to-make-a-kaleidoscope https://abakcus.com/diy/how-to-make-a-kaleidoscope Three strips of mirror in a kitchen-roll tube and a pinch of beads. Turn it to the light and a jumble of sequins becomes a perfect, ever-changing pattern.

Three strips of mirror in a kitchen-roll tube and a pinch of beads. Turn it to the light and a jumble of sequins becomes a perfect, ever-changing pattern.

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]]> Mon, 09 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Pinhole Camera From a Shoebox https://abakcus.com/diy/how-to-make-a-pinhole-camera https://abakcus.com/diy/how-to-make-a-pinhole-camera A shoebox, a square of foil and a needle. Prick one tiny hole and the world outside appears on a paper screen, in colour, moving and upside down.

A shoebox, a square of foil and a needle. Prick one tiny hole and the world outside appears on a paper screen, in colour, moving and upside down.

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]]> Mon, 09 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Hexaflexagon From a Strip of Paper https://abakcus.com/diy/how-to-make-a-hexaflexagon https://abakcus.com/diy/how-to-make-a-hexaflexagon A strip of ten paper triangles folds into a hexagon with three faces instead of two. Pinch, push and open, and a face you never coloured blooms from inside.

A strip of ten paper triangles folds into a hexagon with three faces instead of two. Pinch, push and open, and a face you never coloured blooms from inside.

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]]> Mon, 09 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Wooden Domino Row Building Machine https://abakcus.com/diy/how-to-make-wooden-domino-row-building-machine https://abakcus.com/diy/how-to-make-wooden-domino-row-building-machine A little cart with a cam on its wheel lays a row of perfectly spaced dominoes as it rolls. Then knock the first one and learn why a domino can topple one half as big again.

A little cart with a cam on its wheel lays a row of perfectly spaced dominoes as it rolls. Then knock the first one and learn why a domino can topple one half as big again.

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]]> Sun, 08 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a LEGO Macintosh Classic With an E-Paper Display https://abakcus.com/diy/how-to-make-lego-macintosh-classic-with-an-e-paper-display https://abakcus.com/diy/how-to-make-lego-macintosh-classic-with-an-e-paper-display A Raspberry Pi the size of a stick of gum, a screen made of electric ink and a case of grey bricks. Build a working mini Macintosh and paint pictures in black and white.

A Raspberry Pi the size of a stick of gum, a screen made of electric ink and a case of grey bricks. Build a working mini Macintosh and paint pictures in black and white.

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]]> Sun, 08 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make Forts at Home With Blankets, Chairs and Pegs https://abakcus.com/diy/how-to-make-forts-at-home-by-ikea https://abakcus.com/diy/how-to-make-forts-at-home-by-ikea Two chairs, a broom and the biggest blanket in the house. Build a fort that stays up, find the slope that gives the most room, and learn why triangles never wobble.

Two chairs, a broom and the biggest blanket in the house. Build a fort that stays up, find the slope that gives the most room, and learn why triangles never wobble.

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]]> Sun, 08 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) Homeschool Math: A Complete Guide for Parents https://abakcus.com/homeschool-math https://abakcus.com/homeschool-math Everything parents ask about homeschooling math: how it works, what the law asks, curriculum compared, elementary to high school, supplies, costs and the hard days.

Everything parents ask about homeschooling math: how it works, what the law asks, curriculum compared, elementary to high school, supplies, costs and the hard days.

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]]> Sun, 08 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) Cambridge Math Reading List: 54 Books Before a Maths Degree https://abakcus.com/book-lists/cambridge-math-reading-list https://abakcus.com/book-lists/cambridge-math-reading-list Every year, the University of Cambridge hands sixth-formers who want to study mathematics the same list of books. You do not have to read any of them. Most people who get in have read a few.

Every year, the University of Cambridge hands sixth-formers who want to study mathematics the same list of books. You do not have to read any of them. Most people who get in have read a few.

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]]> Sun, 08 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Decorate Power Cords With Washi Tape and Leather Ties https://abakcus.com/diy/how-to-make-a-decorative-power-cords https://abakcus.com/diy/how-to-make-a-decorative-power-cords A grey extension lead, a few rolls of washi tape and some leather scraps. Wrap it in bright bands, make snap ties for the spare length, and learn why coiled cords run hot.

A grey extension lead, a few rolls of washi tape and some leather scraps. Wrap it in bright bands, make snap ties for the spare length, and learn why coiled cords run hot.

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]]> Sat, 07 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Rocket Man: A Cardboard Box Rocket for Kids https://abakcus.com/diy/how-to-make-a-rocket-man https://abakcus.com/diy/how-to-make-a-rocket-man A big packing box, yogurt pots and cotton reels become a rocket a child can climb inside, and a way into the equation that makes real rockets almost all fuel.

A big packing box, yogurt pots and cotton reels become a rocket a child can climb inside, and a way into the equation that makes real rockets almost all fuel.

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]]> Sat, 07 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Paper Rocket Garland With Slotted 3D Rockets https://abakcus.com/diy/how-to-make-paper-rocket-garland https://abakcus.com/diy/how-to-make-paper-rocket-garland Two flat paper rockets and one slit each. Slot them together, string a fleet along a cord, and the cord draws a curve that took mathematicians fifty years to solve.

Two flat paper rockets and one slit each. Slot them together, string a fleet along a cord, and the cord draws a curve that took mathematicians fifty years to solve.

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]]> Sat, 07 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Color-Coded After-School Routine Clock https://abakcus.com/diy/how-to-make-color-coded-after-school-routine-clock https://abakcus.com/diy/how-to-make-color-coded-after-school-routine-clock A plain white wall clock and five pots of paint. Paint each part of the afternoon as a slice of the face and the hour hand shows what comes next.

A plain white wall clock and five pots of paint. Paint each part of the afternoon as a slice of the face and the hour hand shows what comes next.

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]]> Sat, 07 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make Melted Crayon Art With a Hair Dryer https://abakcus.com/diy/how-to-make-melted-crayon-art https://abakcus.com/diy/how-to-make-melted-crayon-art A row of crayons glued to a canvas and a hair dryer on its hottest setting. The wax melts, gravity takes over, and streams of colour run down until they set.

A row of crayons glued to a canvas and a hair dryer on its hottest setting. The wax melts, gravity takes over, and streams of colour run down until they set.

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]]> Sat, 07 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Moon-Themed Clock With a Moon Phase Window https://abakcus.com/diy/moon-themed-clock https://abakcus.com/diy/moon-themed-clock A full moon for a clock face, a battery movement and a hand-turned phase window. It keeps the time to the second and, with a nudge every few days, keeps pace with the Moon.

A full moon for a clock face, a battery movement and a hand-turned phase window. It keeps the time to the second and, with a nudge every few days, keeps pace with the Moon.

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]]> Sat, 07 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) List of People Who Have Walked on the Moon https://abakcus.com/articles/people-who-walked-on-the-moon https://abakcus.com/articles/people-who-walked-on-the-moon Twelve men, six landings, three and a half years. Who they were, where they stood, and how many of them are still here.

Twelve men, six landings, three and a half years. Who they were, where they stood, and how many of them are still here.

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]]> Sat, 07 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make Geometric Paper Wall Art From Folded Triangles https://abakcus.com/diy/how-to-make-a-geometric-paper-wall-art https://abakcus.com/diy/how-to-make-a-geometric-paper-wall-art Square sheets of coloured paper, one classic origami fold and a board. Fold two dozen identical triangles, turn them this way and that, and a pattern takes over the wall.

Square sheets of coloured paper, one classic origami fold and a board. Fold two dozen identical triangles, turn them this way and that, and a pattern takes over the wall.

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]]> Fri, 06 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make 3D Folding Paper Letters From Flat Nets https://abakcus.com/diy/folding-letters https://abakcus.com/diy/folding-letters A sheet of card, a ruler and some careful folding. Two letter-shaped faces and one long strip make a bold 3D letter; make a few and spell out a name.

A sheet of card, a ruler and some careful folding. Two letter-shaped faces and one long strip make a bold 3D letter; make a few and spell out a name.

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]]> Fri, 06 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Rocket Toy From the Recycling Bin That Flies https://abakcus.com/diy/how-to-make-a-rocket-toy-from-recycling-bin https://abakcus.com/diy/how-to-make-a-rocket-toy-from-recycling-bin A plastic bottle, a scrap of paper and a corner of a cereal box. Roll a rocket, give it fins and a clay nose, then squeeze and watch it streak across the garden.

A plastic bottle, a scrap of paper and a corner of a cereal box. Roll a rocket, give it fins and a clay nose, then squeeze and watch it streak across the garden.

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]]> Fri, 06 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Conveyor Belt Cinema From a Box and Two Tubes https://abakcus.com/diy/how-to-make-conveyor-belt-cinema https://abakcus.com/diy/how-to-make-conveyor-belt-cinema A shoebox, two cardboard tubes and a strip of paper. Turn the crank and the scenery rolls past a cut-out car, which seems to drive though it never moves.

A shoebox, two cardboard tubes and a strip of paper. Turn the crank and the scenery rolls past a cut-out car, which seems to drive though it never moves.

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]]> Fri, 06 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Build a Giant Cardboard Windball From 30 Squares https://abakcus.com/diy/how-to-make-giant-cardboard-windball https://abakcus.com/diy/how-to-make-giant-cardboard-windball Thirty squares cut from old boxes, joined only at their corners. Clip them round rings of three and five and they curl into a ball a metre across.

Thirty squares cut from old boxes, joined only at their corners. Clip them round rings of three and five and they curl into a ball a metre across.

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]]> Fri, 06 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Draw a 3D Hand Optical Illusion With Curved Lines https://abakcus.com/diy/how-to-make-3d-hand-optical-illusion https://abakcus.com/diy/how-to-make-3d-hand-optical-illusion Trace your hand, then draw nothing but lines across the page, each arching up as it crosses the outline. Thirty lines later, your hand rises off the paper.

Trace your hand, then draw nothing but lines across the page, each arching up as it crosses the outline. Thirty lines later, your hand rises off the paper.

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]]> Fri, 06 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Paper Sphere From Six Woven Strips https://abakcus.com/diy/how-to-make-a-paper-sphere-using-just-a-few-strips https://abakcus.com/diy/how-to-make-a-paper-sphere-using-just-a-few-strips Six strips of card, ten pencil marks on each and some patience. Weave them together and they close into a springy ball with 12 pentagon holes and 20 triangles.

Six strips of card, ten pencil marks on each and some patience. Weave them together and they close into a springy ball with 12 pentagon holes and 20 triangles.

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]]> Fri, 06 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Box Kite That Flies Without a Tail https://abakcus.com/diy/how-to-make-a-box-kite https://abakcus.com/diy/how-to-make-a-box-kite Eight dowels, eight bits of tube and two bands of sail. Snap them into two open boxes and you have the kite that lifted a man off a beach in 1894.

Eight dowels, eight bits of tube and two bands of sail. Snap them into two open boxes and you have the kite that lifted a man off a beach in 1894.

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]]> Fri, 06 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Wave Machine From Skewers, Tape and Sweets https://abakcus.com/diy/how-to-make-wave-machine https://abakcus.com/diy/how-to-make-wave-machine Two stools, a strip of duct tape, fifty skewers and a bag of jelly sweets. Tap one end and a wave you can watch ripples down the line and bounces back.

Two stools, a strip of duct tape, fifty skewers and a bag of jelly sweets. Tap one end and a wave you can watch ripples down the line and bounces back.

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]]> Fri, 06 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Harmonograph That Draws With a Pendulum https://abakcus.com/diy/how-to-make-a-harmonograph https://abakcus.com/diy/how-to-make-a-harmonograph A broom handle, a board on a Y of string and a felt-tip pen. Set it swinging and the pen draws figures of eight and woven shells, the shapes of musical harmony.

A broom handle, a board on a Y of string and a felt-tip pen. Set it swinging and the pen draws figures of eight and woven shells, the shapes of musical harmony.

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]]> Fri, 06 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make Moiré Patterns With Two Grids and a Turntable https://abakcus.com/diy/how-to-make-moire-patterns https://abakcus.com/diy/how-to-make-moire-patterns Two squares of black mesh and a turntable. Spin one grid under the other and giant shimmering squares bloom and swirl, a pattern that exists in neither grid.

Two squares of black mesh and a turntable. Spin one grid under the other and giant shimmering squares bloom and swirl, a pattern that exists in neither grid.

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]]> Fri, 06 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make the Missing Square Puzzle and Find the Trick https://abakcus.com/diy/how-to-make-the-missing-square-puzzle https://abakcus.com/diy/how-to-make-the-missing-square-puzzle Four pieces of card make a triangle. Swap two of them round and the same pieces make the same triangle, with a square missing. Where did it go?

Four pieces of card make a triangle. Swap two of them round and the same pieces make the same triangle, with a square missing. Where did it go?

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]]> Fri, 06 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Pendulum Wave Toy From Nuts and String https://abakcus.com/diy/how-to-make-pendulum-wave-toy https://abakcus.com/diy/how-to-make-pendulum-wave-toy Twelve nuts on twelve strings, each a little shorter than the last. Let them go together and they weave waves and snakes, then swing back into a perfect line.

Twelve nuts on twelve strings, each a little shorter than the last. Let them go together and they weave waves and snakes, then swing back into a perfect line.

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]]> Thu, 05 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Galton Board That Draws a Bell Curve https://abakcus.com/diy/how-to-make-a-galton-board https://abakcus.com/diy/how-to-make-a-galton-board A board, forty pins and a handful of beads. Every bead zigzags at random, yet together they pile into the same graceful hump every time: the bell curve.

A board, forty pins and a handful of beads. Every bead zigzags at random, yet together they pile into the same graceful hump every time: the bell curve.

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]]> Thu, 05 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Show the Area of a Circle Is πr² With Paper Slices https://abakcus.com/diy/how-to-show-area-of-a-circle-is-pir2 https://abakcus.com/diy/how-to-show-area-of-a-circle-is-pir2 A paper circle, three folds and a pair of scissors. Cut it into slices, lay them top to tail, and the circle becomes a rectangle that shows why its area is πr².

A paper circle, three folds and a pair of scissors. Cut it into slices, lay them top to tail, and the circle becomes a rectangle that shows why its area is πr².

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]]> Thu, 05 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make Square Wheels That Roll Smoothly on a Bumpy Road https://abakcus.com/diy/how-to-make-square-wheels https://abakcus.com/diy/how-to-make-square-wheels Two cardboard squares, a skewer and a necklace. Trace a hanging chain, turn it upside down for a road, and square wheels roll as smoothly as round ones.

Two cardboard squares, a skewer and a necklace. Trace a hanging chain, turn it upside down for a road, and square wheels roll as smoothly as round ones.

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]]> Thu, 05 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Hyperbolic Slot: A Straight Rod Through a Curve https://abakcus.com/diy/how-to-make-a-hyperbolic-slot https://abakcus.com/diy/how-to-make-a-hyperbolic-slot A pencil, a skewer and a sheet of foam board. Spin a perfectly straight stick and it glides through a perfectly curved slot, thanks to the shape of a cooling tower.

A pencil, a skewer and a sheet of foam board. Spin a perfectly straight stick and it glides through a perfectly curved slot, thanks to the shape of a cooling tower.

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]]> Thu, 05 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Construct the Spiral of Theodorus With a Ruler https://abakcus.com/diy/how-to-construct-the-spiral-of-theodorus https://abakcus.com/diy/how-to-construct-the-spiral-of-theodorus A ruler, a square corner and a pencil. Build one right triangle on another and draw every square root from √2 to √17, curled into a snail shell.

A ruler, a square corner and a pencil. Build one right triangle on another and draw every square root from √2 to √17, curled into a snail shell.

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]]> Thu, 05 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Build a Level-One Menger Sponge From Business Cards https://abakcus.com/diy/how-to-build-level-one-menger-sponge https://abakcus.com/diy/how-to-build-level-one-menger-sponge A hundred and twenty business cards, folded into twenty cubes and locked together without glue. The first step of a shape with no volume and an infinite surface.

A hundred and twenty business cards, folded into twenty cubes and locked together without glue. The first step of a shape with no volume and an infinite surface.

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]]> Thu, 05 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Paper Microscope With a Glass Bead Lens https://abakcus.com/diy/how-to-make-a-5-paper-microscope https://abakcus.com/diy/how-to-make-a-5-paper-microscope A strip of card, a glass bead the size of a grain of sand and a slip of sticky tape. Hold it to your eye and an onion skin becomes a wall of cells.

A strip of card, a glass bead the size of a grain of sand and a slip of sticky tape. Hold it to your eye and an onion skin becomes a wall of cells.

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]]> Thu, 05 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Balance Bird That Perches on Its Beak https://abakcus.com/diy/how-to-make-a-balance-bird https://abakcus.com/diy/how-to-make-a-balance-bird A bird cut from card, two coins and a fingertip. It balances on the very tip of its beak, rocks when you nudge it, and settles back, as if it had decided to stay.

A bird cut from card, two coins and a fingertip. It balances on the very tip of its beak, rocks when you nudge it, and settles back, as if it had decided to stay.

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]]> Thu, 05 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) How to Make a Fire Extinguisher With Baking Soda and Vinegar https://abakcus.com/diy/how-to-make-a-fire-extinguisher https://abakcus.com/diy/how-to-make-a-fire-extinguisher A jar, some baking soda and a splash of vinegar. Tip the jar over a candle as if pouring water, and the flame goes out, smothered by a gas you can’t see.

A jar, some baking soda and a splash of vinegar. Tip the jar over a candle as if pouring water, and the flame goes out, smothered by a gas you can’t see.

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]]> Wed, 04 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya) Metal Etching: How to Etch Steel With Salt Water and a Battery https://abakcus.com/diy/metal-etching-science-experiment https://abakcus.com/diy/metal-etching-science-experiment A scrap of steel, a bowl of salt water and a 9 V battery. Draw on the metal, switch on, and twenty minutes later your drawing stands proud of a surface the current has eaten away.

A scrap of steel, a bowl of salt water and a 9 V battery. Draw on the metal, switch on, and twenty minutes later your drawing stands proud of a surface the current has eaten away.

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]]> Wed, 04 Nov 2026 00:00:00 GMT ali@abakcus.com (Ali Kaya)