Source: brucedickinsonmaidenFear of the Dark
Source: matthenIf you roll a circle inside one 3 times its size, it will actually trace out a 4 pointed star shape called an Astroid (this shape is traced out in the animation in orange). But what if inside the smaller circle, there is an even smaller one tracing out a smaller Astroid? This animation shows the intricate shape that is generated by adding the effects of all the Astroids. [code] [also]
A hypotrochoid is a roulette traced by a point attached to a circle of radius r rolling around the inside of a fixed circle of radius R, where the point is a distance d from the center of the interior circle.
(via violent-buddhist)
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