Stackable 35mm Film Case

UPDATE: To download and print this, please go to my Printables profile for the files.
(https://www.printables.com/social/100900-thinbegin/models)
I no longer use Thingi, but have left the design description in place for reference.

This case is a mod/remix of, and extension from, two other models that can be found on thingivers.com, where one of those was a mod/remix of the other, so this is a mod/remix of a mod/remix. The original design (as far as I know) was a case that held four 35mm films, and the second design took that and just removed on of the four, leaving room for three 35mm films, for compactness.

Original design (by roflkatofl):
https://www.thingiverse.com/thing:1750288

Remix/Mod of original (by rodgsilva):
https://www.thingiverse.com/thing:4417630


I took those two models, and decided to make some changes, both major and minor. Here are the noticeable things that I (hopefully) improved.

++ 1) Made the cases stackable, or semi-interlockable, should you d