I just got Turing Tumble for Christmas, after flipping through some of the early challenges I skipped straight to the back. This was the first one I really tackled. It was fun because I wasn’t primed to solve with expected answer based on earlier solutions.
While trying to write this post using Lodes emulator I found I could actually get the right solution with 17 parts! If this isn’t legal then surely I get some extra credit for solving it on nearly half the board space.
Realistically the physical solution I originally worked on got much more consistent results using 22 parts. It was at least as consistent as passing the balls through more green parts. https://www.lodev.org/jstumble/?board=11r01rer0ileerrlfrxfelrflereelfelzl_16_16
Is speed of execution a thing? Because this solutions is probably the fastest so far! Catching the red ball near the top and passing balls in the same direction (keeping up momentum) help a lot. Even without taking shortcuts this 25 part solution is pretty fast.