For more than five centuries, Leonardo da Vinci’s Vitruvian Man has invited admiration but also bafflement. With its ...

One way to draw a Reuleaux triangle is to start with an equilateral triangle, which has three sides of equal length. ... Indeed, the rounded triangle can rotate freely inside the square.

First, we have groups. To take a straightforward example, consider the six symmetries of an equilateral triangle: Two rotational symmetries (by 120 and 240 degrees) Three reflection symmetries (across ...

Draw any equilateral triangle with side length 1. All three vertices are a distance 1 from each other, and at least two of them must be the same color, whether red or blue.

Henry Dudeney, a self-taught English mathematician and puzzle columnist, asked his readers to dissect an equilateral triangle into the smallest number of pieces that could be rearranged into a square.