## Hypocycloid

A hypocycloid is a special plane curve generated by the trace of a fixed point on a small circle that rolls within a larger circle. It is comparable to the cycloid but instead of the circle rolling along a line, it rolls within a circle.

Some special cases of hypocycloid:

a = 1/4: astroid

a = 1/3: deltoid

a = 1/2: straight line

a = 1: circle curve

a = 3/2: nephroid

a = 2: cardioid

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