i like crocheting these circles. not following a pattern, just trying to keep them flat as they grow. then a little bumpy edge to make them look almost like gears. i made a set of four yellow ones for coasters and the big red one for under a plant. the red yarn is from an unraveled cotton sweater. this is addictive, i already made four more (coater-sized) since i took these photos!
notes: i used a D/3mm crochet hook. the whole thing is single crochet with a sort of picot edge. if they do end up a little wavy/bumpy, leaving them under a heavy book overnight flattens 'em right out. a fun project for keeping hands busy while watching movies!