Makerpipe ( https://makerpipe.com/ ) is this fun Kickstarter that makes connectors that allow you to use inexpensive EMT (Electrical Conduit) for creating things. It's kinda like having an Erector Set for adults.
I hope they plan to roll-out more connectors. I made this sliding EMT pipe cross-over that allows you to make moving parts. There are Hand Bolts that can be tightened to lock the position of the two conduits.
I've been using Makerpipe on my Solar eBike Trailer Project ( https://youtu.be/F27a7yQKD6s )
The author hasn't provided the model origin yet.