Let your imagination run wild stacking rounded off squares. With essentially an infinite number in the customizer of choices you can be assured no one will have an object just like your's. By changing the dimensions you can make planters, trays, bud vases, pencil holders, bracelets, or drinking glasses. The simpler smaller objects make good demonstration pieces and will print quite quickly.
Run the customizer and choose your parameters. The key parameter to have different roundness is the Radius of Curved Edge. Be careful to avoid large overhangs. Note that the function which allows for the rounding also slows down the customizer quite a bit so you'll need some patience for this one. It is quite possible to use the customizer to create something unprintable. When slicing specify no fill and no top layers. Once you print it, be sure to upload a photo. I'm curious to see what people end up with. I have several other container customizers with variations on this theme. Check out the "Derived from" to see the other versions.