simple shelf for 2020 profiles

This is a simple shelf for 2020 profiles for tools, a small trash bin or other things to place it during working. I use it on my CR-10S. There are a lot of options - I really like it.

The version on the image have a inner size of 120x120mm, so the stacking box from https://www.thingiverse.com/thing:691127 fits. I use it as trash bin.

I create three versions for you, with an inner size of:

* 150mm x 150mm
* 120mm x 120mm
* 100mm x 100mm

Feel free to ask if you need another size.