Toilets use a lot of water, you know. And it seems kind of strange to have a sink right next to your toilet, pouring all that water down the drain, when your toilet would work just as well with your second-hand sink water as it does with regular clean water. Why not save water by running your sink into your toilet?
This Dual Flush toilet takes that idea to the next level by actually putting a ink in the tank of the toilet. So you can brush your teeth while you pee, or wash your hands before flushing to use the same water for both. Sure, it's kind of an awkward place for a sink, but you want to save the environment, don't you?