My hat comes off for Instructables user calischs. You may have seen stacking metal lunchboxes like this before. They’re apparently called “Tiffin boxes” and have been around since the 19th century. What’s remarkable about this project is not so much the object itself as the awesome improvised tool calischs came up with to make it, a video of which is embedded above:

The can rolling jig consists of two old door hinge pins and a hose clamp. The heads of the hinge pins nest with each other. By applying pressure with the clamp and rolling the can, we can raise a lip on the can’s side.

Pretty impressive results from pick-up material. Looking forward to trying this one myself.