Got stuck on the light puzzle with the four transmitters. The light would not travel through the left hand wall to go to the right hand transmitter, would stop on the wall. The wall did not stop the light when it was white or yellow, but did stop it when it was purple
Hmm. I think the difficulty might have spiked too much for that last puzzle.
The glass/transparent walls are filters for the light. So Blue light can go through a purple window and come out purple. But a blue light through a Yellow filter stops because yellow allows red and green light through, but not blue.