How about grabbing some rectangular pieces of wood, drilling holes through the four corners of each piece, sticking pipes up through the corner holes, and then attaching wheels to the bottom of the pipes. Maybe using some wood glue on the wood to fortify the pipe entry and exit points, with notches in the pipe for holding the wood, etc.
The best strong and light shelving material, if not wood?
For storing tools and whatever other household items. Anywhere between 3 feet and 6 feet tall. I noticed a design is to put two wheels on one side but not on the other, wheelbarrow style.
I'm not trying to invent something, I'm asking for comments and/or other ideas. Naturally I want the movable shelves to be sturdy but light as possible. They will roll on low friction carpet here.