No matter what combination I tried, I couldn't delete the stairs tile in the NW corner. Once one set of stairs was placed along the wall, I could no longer keep a teleporter tile in the very NW corner. I could place one flight against the walls, demolish half and place two new teleport tiles, but as soon as I engaged transparency, the teleporter tile in the very NW corner was erased, leaving a blank floor tile. Does the customization code do that because it thinks that there's a full set of stairs? What's puzzling is that I was able to make the reverse, with the bottom half-flight going along the walls. That isn't the look I wanted, though. After a couple of hours, I gave up and hit on the idea of using a large rock to cover the tile. It works, but it was frustrating not to be able to delete the tile and have a nice big goza platform.