no, the active area of a teleporter is 3*3 blocks above it, so the top one doesn't have to be halfbrick. adding an actuated one could work, but working with floating teleporters is a pain, and even more so with actuated ones. I could try though. if i do, I will post it as a reply in this threadDoes the top teleporter have to be halfbrick for the bottom one to work? If not, you can add another actuated teleporter on the top to make it 20. 16 is probably enough, though.