Recursive
thinking.

Try three interactive experiments and watch simple steps build something surprising.

01

Fibonacci numbers

Every new number is the sum of the previous two. Keep adding to reveal the pattern.

The growing sequence2 numbers
F₀0
F₁1

Press + to calculate the next number.

The ruleF(n) = F(n−1) + F(n−2)
02

Towers of Hanoi

Move the entire stack from tower A to tower C. One disk at a time; a larger disk can never sit on a smaller one.

Moves made
0moves
Best possible
15 moves

Click a tower to pick up its top disk, then click where to place it.

03

Cutting the disk

How many regions can straight cuts create? Draw chords and see how the number changes.

Total regions
1
Lines drawn
0

How to draw: Click two different points anywhere inside the circle. The line extends all the way to the disk's edge.

Choose the first point to start a cut.