But sacred geometry is a broad term, covering a range of interpretations by tattoo artists around the world. First timers looking for new inspiration may be in need of an expert on the subject.

But why, then, does geometry sometimes seem so difficult? "My guess is it's difficult because it focuses on proofs," says Spelke. It's not enough to have the intuition that we apparently all share.

We’ve all learned “parallel lines never intersect” in high school geometry. But what your teachers failed to explain is that “parallel lines never intersect” is only true in Euclidean ...

Mountain bikes are constantly changing—what counts as outdated versus new-school mountain-bike geometry these days?