Hmm, I might be thinking of the old server, or of someone else's hole. Something has a big long ladder all the way up, and a section where the whole wall is covered by ladders.
It can be 2x anything if you have all the pistons on the bottom/top (or anything x2 if you have them on the sides). I guess you could potentially go bigger if you have pistons pulling pistons pulling pistons but the wiring would be prohibitive (and impossible to hide) to say the least.