Adding a swimming pool or hot tub means displacing something else – usually a outdoor lawn, yard or deck or dedicated room inside a house. But what if you could have the best of both worlds: a usable space or surface replaced by a body of water when you want it?

These designs effectively let you walk on walk on water, in a sense, thanks to dynamic and on-demand functionality right beneath your feet. Designers of the exterior and interior swimming and wading pools (as well as hot tubs) shown here include companies like Hydrofloors (images above) and Agor (video below).

At the push of a button, decking descends autometically and water fills in the void left behind – conceal, reveal, rise and repeat as desired, turning a cocktail into a pool party and back again.

Depending on the nature of user needs, the mechanically-controlled platforms lower to become pool bottoms but also steps down into the resulting water.

Aside from issues of cost (and one can only imagine how expensive such custom solutions must be – there are no list prices), the question that remains, of course, is: how hard is it to clean and maintain? Perhaps if you have enough money to afford to build one of these liquid luxury machines, that price point is moot.