I spent about 3 hours today turing some 1"x1" angles into lightweight wheel chocks. They are about 6" long, with 9/16" lightening holes, cut with a pilot hole and a unibit.
I need to buy some light nylon line, like parachute cord, to connect them together in pairs. I will drill a small hole in the corner of each, insert the line, and tie a knot.