Nifty illusion,but they must have to have someone on hand to constantly pick out any bits of dust and leaves that fall into it, spoiling the effect.
'Wowee the water's going uphill! Oooh and there's a magic leaf swimming against the flow, downhill!'
I guess it's constantly filtered to keep the water crystal clean.
Reminds me a bit of those 70's garden taps hanging from a thin chain with an 'everlasting' stream of water falling inexplicably from them, which actually was pumped up a clear tube within the stream of water itself. Kinda cool the first time you see one, but after that, somewhat tacky.