In front of your Apple Store in the EWBWCollab world (starting with EWBWCollab4 01/04/2013) there is this pool or fountain, filled with half-high water "slabs". I put a few fence blocks in for the photo just to make it obvious:
It's not normal water: it's half as high as normal. The water is all "slabs" to use the Minecraft term.
The normal way to make slabs is to place some water and let it flow, then remove the first water block and very quickly save and exit. But it requires really quick timing and I don't think you could do that a hundred times! 8-O
Okay, kewl. I figured out that I can get five blocks each time, so I see that it really only took about 30 repetitions to make all three fountains. It's pretty cool effect. The ivy seems to make a good trap for creatures, I'll have to do some experiments (MWAH-HA-HA-HA-HA!!!!)