I've always loved genetic algorithms. Design is exploration, and what better way to explore than evolution? The idea: lay out hundreds of marks on a grid, pick the ones you like, and let them breed.
Everything runs in your browser on Web Workers, about 15 ms a mark. A run is a seed and your clicks, so Replay grows it again exactly, fonts you added included; the address holds the screen (#s=) or the run (#r=).
Made by @nintharc on X. The marks above are from my own Saved list. as one HTML file that runs offline.