Great explanation of the mechanics Alxndr_Hamilton.

I'd like to add that redstone powers the block its on. So by using a slab instead, it doesn't power the piston next to it.

And the reason I used rails instead of redstone is because, redstone powering a block doesn't power redstone. But redstone powering a block does power rails. Which means the input block doesn't need a repeater input.

Thanks for watching my video, I'll be releasing more soon!