I made this for my kitchen window (see photos). I needed a good place for trailing plants to grow that were out of the way. 

There are two models to choose from for rounded or 90-degree corners.

Prints very easily, though for the rounded bottom you may need supports if your printer doesn't handle bridging/overhangs well. I printed without supports and had fairly rough corners that needed sanding and filling before I spraypainted them white.

Enjoy!