More distractions via redstone as I wondered whether it was possible to make a "lift" using sticky pistons. It seemed easy enough to make each piston extend, but retracting each one, and then finding a way to pull the pistons back down to their original place was tricky. However, it *IS* achievable, although it takes up a lot of room, uses an unbelievable amount of redstone and repeaters, and would be much easier just to place a flight of stairs in a building instead.
I tried to colour code the design and so white wool carries signals to extend the pistons (they are inside the purple "floors" area), red wool carries the signals to retract the pistons, whilst the blue wool is a looping section that forces the pistons to extend and pull down the piston above it until all pistons are in their original position. In the second image you can see the height that the "lift" travels between floors (just 6 blocks!).
The lift is operated on each floor by a lever, and these are connected to a XOR gate (seen in the second image on the purple blocks of floor1).