You know how you whittle and whittle away at a bar of soap until it's so small it eventually slides out of your hands and down the drain? If you had a Soap Bank, you'd save all of those slivers like pennies, until finally there's enough of them to help you get clean again.
The Soap Bank attaches to your wall by way of a suction cup and works just like a soap tray, except for it's got a thin opening cut into its rubber dish. Once your bars get too small to be usable, they'll just fall into the Bank's netting underneath and will continue to collect there as you shower. Eventually you'll have enough caught in the net that you can just wet it and soap your hands up.
The Soap Bank isn't available yet as it's still a concept — and quite a good one — by Designodoubt