This is a simple and easy-to-make floor selector, using a minecart and water as it's main transportation method.

I wanted to make use of the 'observer leaf-wires' for this vertical setup and found out that you can have them next to each other, as long as you make them 6 blocks. (makes sense) Hopefully the leaf wires will stay!

-Can be expanded with a lectern.

Made with: Java Minecraft 1.14+

Note: Due to the remake, one little situational quirk remains: For each full cycle, you may have to put it to the 7th floor (the highest selectable floor) for just a moment, in order for some diagonal water to be removed.

edit: corrected Note info.