A sieve to pre-sort your Lego(TM) bricks from large to small.
I have not printed and tested them yet. The hole sizes need to be tested and evaluated
Either print the STL directly or use the scad file in OpenScad and adapt to your needs.
The two most important variables are
sieve_size - the size of the holes in the bottom. Change this for which bricks you want to filter. diameter - the outer diameter of the walls. Change thi to whatever your printer supports.
Print and try. Find out which hole sizes are the best.