The past few months I've been obsessed with the game Opus Magnum on Steam. It's a Zachtronics game where you build a contraption to complete a goal, but then optimize it to make it as fast/small/cheap as possible. Optimizing for speed, in particular, is insanely addicting. Apparently, SpaceChem used to be on the iPad (a similar, but older, Zachtronics game), but I no longer have an iPad and I don't think the game is available anymore anyway. The closest thing I've found on iOS that is currently available is [the Sequence], which seems very similar to Opus Magnum and SpaceChem but is unfortunately not very open-ended so you can't make a solution and then optimize it over and over like in Zachtronics' stuff. Are there any other games on the AppStore that fill this very specific niche?