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 hinge that allows you to make moving parts with the EMT conduit. There is a Hand Bolt that can be tightened to lock the position.
I've been using Makerpipe on my Solar eBike Trailer Project ( https://youtu.be/F27a7yQKD6s )
The author marked this model as their own original creation.