This hat has four dropped stitches which mean relatively little yarn goes a long way around the head. The potential to stretch means one size fits a small adult head up to a large - the biggest comfortable fit was on a 58cm head. The pattern can be made with one average 50g ball of aran weight yarn, so this might be the way to use up a lonely leftover. I used some handspun North Ronaldsay with coloured bits in it, but I think the snakes might be shown off better in a plain colour.