I figured out what sort of mechanism I need for the challenge, but my attempts to actually construct it keep falling short.
Click here to view the secret text
×My overall plan is:
-1. Get one gel baby ahead of the rattlesnake, and get the other stuck behind it. I've figured out how to do this.
-2. Get the rattlesnake moving in a loop, so the lagging gel baby only makes progress slowly.
-3. When the lagging baby finally reaches the rattlesnake's area, it breaks the loop and the rattlesnake can leave.
-4. Then the baby arrives, hopefully after the fuse has gone off, and the rattlesnake gets stuck on the plate after it.
My problem is setting up the rattlesnake loop. I can't figure out how to make a loop that it will leave. My best attempts keep failing because I can't get the different exit tiles to lead to paths of the right relative lengths, or because I unbrain the snake and am trying to make a loop of length 8 work, as a length 10 loop doesn't seem to delay the baby enough. In this case, the loop won't be consistent and the snake gets trapped.
I may also need help making the baby's path long enough, but I'm not even at a point where I can test that yet so I'm not especially concerned about it right now.