Cut off the hemmed bottom of all shirts and discard.
Cut one shirt into one-inch horizontal strips so that they are loops. You will need 14 strips.
Stretch these loops in pairs around the hula hoop in a pinwheel pattern. You should have seven pairs of loops equal distance apart.
Start cutting shirts into one-inch strips. This time you will want to cut the loops so you have long strips of fabric.
Then weave these strips in and out of the loops that are on the hoop already. Go over and under as you weave. Just tuck in the ends and continue with a new piece as needed. Treat the pairs of loops as one.
Once you have about an 8-inch diameter rug, you will want to separate the loops that are on the hula hoop and start going over and under them individually.
Once your rug is 6 inches or so from the end, you can actually separate the loop itself and treat each piece as an individual as you weave over and under.
When you are happy with the size, just cut the loops from your hoop and tie them in a double knot. You can leave these ends as fringe or tuck them in.