All Interactives (59)
Showing 59 of 59 interactives
A Mind-Reading Effect
Twenty-five cards, one riffle shuffle and two deals into five piles, and the arrangement survives. A Gilbreath effect you can step through.
Akkam Pakkam
Place shared dice sums on a private grid, score equal neighbors, and play live with a classroom leaderboard.
Ascending-Descending Grid Puzzle
Fill a grid with numbers that are ascending in rows and descending in columns. A constraint satisfaction puzzle!
Assisted Game of Nim
Learn the XOR strategy! Visualize how powers of 2 determine winning moves with color-coded borders.
Baby Hummer
Four cards, a few cuts and turns, and the card you noted ends up facing the other way from the rest. Try it, then see why parity makes it unavoidable.
Bagchal Game
Play the traditional Nepali board game where tigers try to capture goats while goats try to block tigers.
Balanced Ternary Representation
Explore balanced ternary using digits T (-1), 0, and 1. Add or subtract powers of three to match the target number.
Binary Number Representation
Learn how numbers are represented in binary (base-2) format through an interactive guessing game.
Binary Search Magic Trick
Perform an amazing magic trick that reveals how binary numbers work. Think of a number and watch the magic happen!
Black Hole
Play on pyramids, grids, paths, and rings with a friend, an online opponent, or AI; run and study persistent experiments with Laya and Jev.
Bulgarian Solitaire
A mathematical card game where you repeatedly redistribute cards into piles until reaching a stable configuration.
CATO Target Puzzle
Reach a target arrangement of face-up and face-down cards using only cuts and turn-over-two moves. Some targets are impossible: can you tell which?
Chessboard Repaint Puzzle
Repaint rows, columns, or 2x2 squares to achieve exactly one black square. A puzzle about parity and operations!
Computing π from Coin Tosses
Toss a coin until heads first outnumber tails, record the fraction, and repeat.
Craps: An Exploration
Experience the classic casino dice game! Roll two dice and learn about probability as you discover the rules of the opening throw.
Cross Window Puzzle
Can a 4×4 grid give every cell a unique cross-shaped neighbourhood? Hunt for two matching crosses, or colour your own grid and watch the collision appear.
Cut and Turn Over
Ten cards, cut anywhere, turn the top two over, repeat. Watch an invariant hold, then fold the packet and find exactly five face up every time.
de Bruijn Comb
A comb exposes four of eight positions as it slides along a 16-bit cycle. Watch all sixteen four-bit reads come out distinct.
de Bruijn Torus
Slide a 2×2 window around a 4×4 grid of bits that wraps at the edges. Every position shows a different pattern: the idea behind position-coding in robotics.
DNA and the de Bruijn Graph
Type a DNA string, see which triplets light up on the sequencing array, and watch an Euler path through the de Bruijn graph read the sequence back.