warning: bridges galore, or retraction galore.
pretty much the same as jewzaams version, except this allows you to change the floor so it aligns with the walls, and allows you to change the slot length on the sides separately from the main slots (allowing for easy removal of that pesky center pillar on the sides (i like 40x40x150 boxes with 25mm slots, but this results in the small sides having short lengths (like 10-50 mm slots, thus making a ugly pillar in the middle of them.
purely cosmetic changes, but the lids will fit the original box as long as wall thickness, and box size match both files (height dosent matter)
included with this thing is the modified scad, and a pre rendered file with 40x40x150, with 2mm walls.
do note i have replaced the SCAD and STL with a new version since i made a change immediately after uploading.