I did one of these. It was fun. Sew 40 strips end to end. Cut off 18 inches at one end, bring the ends together and sew down the long strip, 1/4 inch seam. When you get to the bottom, cut off the end, then bring the ends together and sew another 1/4 inch seam down the length of the long strip. Keep doing that. It's fun and it's fun to see what your top looks like at the end.