How it works
Forty-eight pictures to build on the Pythagorean spiral, the wheel of right triangles a math class draws. Each idea says which triangles carry which part and the color order across them.
Read the full guide
Draw the wheel in four steps
1. Draw a right triangle with two short sides of the same length. Call that length 1. 2. On its long side, stand a new right triangle whose outer short side is also 1. 3. Keep going: each new triangle stands on the long side of the last. 4. Stop at triangle 16, the last one that does not overlap the first.
Wheel of Theodorus art ideas, by how much you add
Easy ideas keep the wheel whole: color the triangles in turn and add a head, a body or a handle. Medium ones add a detail or a planned color order. Hard ones add a second wheel, a pattern inside every triangle or a scene around it.
- The long sides measure the square roots of 2, 3, 4 and so on, up to 17.
- Number the triangles lightly in pencil before you color, so the color order comes out right.
Questions and answers
Is the Pythagorean spiral the same as the wheel of Theodorus?
Yes. Wheel of Theodorus is a classroom name for the spiral of Theodorus, which is also called the square root spiral, the Pythagorean spiral and Pythagoras's snail: right triangles placed edge to edge around a point. It is named after Theodorus of Cyrene.
How many triangles are in a wheel of Theodorus?
Sixteen fit before the wheel overlaps itself. The sixteenth triangle, whose long side is the square root of 17, is the last that does not overlap the first. The spiral can be continued past that, winding over itself.
What can you turn a Pythagorean spiral into?
A snail is the closest fit, since one name for the construction is Pythagoras's snail. This list also has a peacock showing off the wheel of triangles, a chameleon ending in the triangle wheel and a paper fan with a slat for each triangle.
How do you color a Pythagorean spiral?
Give the colors an order and repeat it around the wheel: two colors in turn, six rainbow colors starting again at triangles 7 and 13, or four bands of four. Every idea names its own order.