Rowan had some interesting homework with a protractor. I broke out Processing.js again to play with it.

Press the key “o” to start and stop the dizzying animation. Press “a” to shorten the base of the triangles that radiate out from the center, and press “s” to lengthen the base. Click the mouse to set the distance of the base of the first triangle from the center. The succeeding triangles distance from the center point is a function of maintaining a right angle at the base, and the fixed base length. Wert is there just for fun.