A model of the famous toy known as a spirograph. A circle of radius r (see blue circle below) is allowed to roll around the inside of a circle of radius R (see black circle below). We assume that the ...

From the twisted mind of brusspup comes another brain-hurting illusion. This one is really, really convincing, so tell me: When you look at this video, you’re seeing a circle of eight dots rotating as ...

Have you been left in awe by the stunning intricate designs created by a pen and gears by seemingly following the same pattern of movement over and over again? Did you wonder "How the heck is that ...

In space, most orbiting objects will have circular- or elliptical-shaped orbits. But now, almost 30 years of observations has revealed that a star in the center of our galaxy orbits the supermassive ...