Cylinder Locking Mechanism

Here is a concept that will be useful if you ever need to work with cylinders, interlocking tubes, bottles, etc.

When I think of joining two cylindrical objects, I immediately think of screw threads. Bottles and caps, pipes and joints, etc. While screw threads can be 3D printed, they're not optimal and usually a waste of time.

The other thing that looks like it works is the tongue and groove mechanism. However a standard rectangular tongue and groove means horizontal overhang which 3D pri