I've come a long way since I last made burpies for little I. I have greatly improved them and sad his were not so pretty. Cut me some slack that is the first project I did when I bought my sewing machine 2 years ago!
I made 8 with the "original" pattern, curved edges. I also made 4 rectangular cloths with cotton fabric on one side and terry cloth on the other. I realize only one side is really usable for the intended purpose of spit up, but there are so many more options for cute fabric. Or in my case, an old dress, husband's old shirt and some extra cute fabric I had lying around.
Simply cut out your desired shape, really you can't mess this up! Cut another piece with an old hand towel, terry cloth or what ever you have.
Sew right sides together, leaving an opening for turning
Turn right side out and iron flat
stitch around the outer edge, sewing up the open gap