Extendable trays

While ago i made these trays. They stack using posts UP or sideways.
I've used them for years and they work great.
Post come in 2 printable configurations, vertical and horizontal. Print which ever works for you. I used vertical.

I included 2 inner trays just so you can see what you can create your self.
Obviously i wont be making inner trays of multiple configurations, so you need to do that your self to accommodate your personal need.