"Granny square" crochet ball.

Crochet 6 granny squares and double them with felt (if you want to make a ball). If you'd like to get a nice baby block - use non-stretch fabric. Assemble your squares as shown and stuff firmly. I use fabric scraps shredded to small pieces to staff some of my toys. This way I can recycle all of my leftover fabric and make toys nicely weighted.