By yielding on every iteration you're restricting your simulation to at most 60 steps per second, because Observable uses requestAnimationFrame() to produce new values from a generator cell. I would instead suggest to only yield every nth frame. E.g., this would yield every 100th frame: let n = 0; while(true) { // ... if(++n >= 100) yield (n=0, context.canvas); }

Thanks! I was indeed wondering how to speed it up

Small correction of my earlier comment (for posterity): "I would instead suggest to only yield every nth iteration. E.g., this would yield every 100th iteration:"