Been dreaming about making this sort of box for years and couldn’t figure out how. Onshape has a plug-in that does all the tabs. Lots of box makers will figure out fingers for exterior corners, but this one (finally) does it for interior pieces. So imagine a box for batteries that has two interior levels to secure the batteries standing up on end (and not touching each other). This box was made for fountain pins in the big section and sample ink cartridges because the ink cartridges leak when they fall over. So excited!
