Timeline becomes useless pretty quickly

[ChrisKnott]

Most algorithms will very quickly just become full lines of squares on every line. This needs to show more useful information at zoomed out scales.

This is an engineering challenge because there might be millions of steps that can't be rendered individually. The current rendering is smooth because it relies on the fact that squares merge into each other.

One nice design might be some kind of "heatmap" that shows the density of the visits to that line, rather than just flat colour. This would require a clever data structure to do efficiently.