Melting walls, anyone?

Next year, visitors to the EXPO in Saragossa will be able to contemplate and even visit a building that brings a new meaning to the phrase "melting walls".
The building's walls will be literally made of water - little "waterfalls" spilling from closely spaced valves along the roof. When someone approaches the pavilion, suddenly the water curtain will disappear before him or her, allowing entrance. This will be possible thanks to a digital control system. Even images or texts can be "painted" on the walls by opening and closing the right valves.

I'll conclude with a joke that also can form a link between psychedelia and the idea of the Water Pavilion:

Three guys are walking around the city: one of them is on speed, the other one on acid and the third one on pot. Suddenly they find themselves in a dead end.
- Let's smash this wall! - says the guy who is on speed.
- Can't we just walk through it? - asks the one on acid.
- Come on, guys, let's go home! I'm hungry - the one who is on pot answers.