We embedded a 16 mm pipe near the surface of a concrete wall to guide some electrical wiring. I needed a very short tee-section, to have the entrance/exit holes perpendicular to the wall and this is the result. Commercial 90 degree bends have a large radius of curvature, that requires rather deep cuts into the wall for the same effect.
The design has a transitional fit for common 16 mm PVC pipe. I have included the Fusion 360 models for you to play around with. The design features end stops for the pipe sections and chamfers for auto-centering when you push this onto a pipe.
I have also included a curved end cap, so that feeding in the cable is easier (it bumps into a curved surface that guides it into/out of the pipe) and a pipe section with a circular cut-out that can be used as a temporary plug, or to really make it into a tee-section.
The author hasn't provided the model origin yet.