This page has the "zooming in" animation and a good explanation: https://sites.math.washington.edu/~conroy/general/weierstrass/weier.htm https://sites.math.was

This page has the "zooming in" animation and a good explanation: https://sites.math.washington.edu/~conroy/general/weierstrass/weier.htm https://sites.math.washington.edu/~conroy/general/weierstras... It's mentioned in the Wikipedia article: "The Weierstrass function could perhaps be described as one of the very first fractals studied, although this term was not used until much later. The function has detail at every level, so zooming in on a piece of the curve does not show it getting progressively closer and closer to a straight line." Does anybody know any even earlier "fractal studied" before they were named so? I guess the author probably meant "Bolzano function" (~1830, published in 1922, mentioned in the Notes section).