Cotton fabrics, cotton embroidery floss.

Technical challenges:  Took a Zoom class to learn this quilting technique, which originated in India. It involves making an entire quilt from the outside in, working your way around the outer edge of the backing material and quilting the batting and top pieces in concentric layers towards the center. You are doing everything -- top, batting, backing, quilting -- in one step. Keeping all the pieces and edges and layers and stitches under control seemed impossible at first, but once you get going it's actually a lot of fun.

Take-aways:  Next time, if there is a next time:  (1) Baste the batting to the backing. (2) Working without pins is for experts only. (3) Sometimes it's amusing to do projects in colors I think I hate.