This is a very basic stackable rack. Inspired by all the stackable 3d printed racks like rhese:

• https://www.printables.com/model/88181-stackable-electronics-mini-rack 
• https://www.printables.com/model/406228-taller-stackable-electronics-mini-rack 
• https://www.printables.com/model/58441-118-car-model-stackable-rack 
• Etc.

The width and length were made to “squeeze” fit plastic food container, i.e., the container is squeezed a bit when you push it in or pull it out.

Just print 6x6mm square bars with your desired height, 80mm square bar included.

Not for heavy objects.