The idea came from here to use some old T-shirts instead of throwing them away: T-Shirt Weaving . Something to do with the grandchildren during break.
A good way to link the strips together without sewing is found here: Making Fabric Into Yarn.
In this case the T-shirts were cut straight across:
The loom was made from a large piece of cardboard, and the warp threads from collected string and yarn. A ruler and yarn needle made the weaving faster.
The result was a small mat or rug.