Simple stackable box without dividers with back support

The model I remixed this from didn't have adequate support in the back. The front of the container had a flat track for the container on top to sit on. In the back of the container, it relied on a beveled (inward) lip. This causes the back of the upper container to slip down just a little bit in the back. When stacking 3+ containers, you can start to see the container tack leaning back.

See the photo of 12 stacked containers for an example. The top 3 containers (white, black, and gold) are this updated model with back support and the 9 containers under those are the original model where the back lean is present.

To fix this, I added a flat track in the back for the upper container to sit on, just as there is in the front. This prevents the back from slipping down even a little.

I'm sure most people won't stack more than 3 or 4 of these, but even stacking 4, this lean is pretty noticeable. Well, here is the fix for this.

I only modified the “large” model file because I never used the “medium” one.