DD has shoulder length hair that is curly round her hair line but straighter on top. When she was younger it was shorter and curlier all over.
She had a hair cut the other day and the hairdresser said she'd put some layers in to bring back the curl. I can see that the shortest bits are sitting about an inch higher than the longest bits, but it's made no difference to the curl.
Does she need to get shorter layers higher up her hair? Or is there some magic equation for the length of the shortest bits in relation to the longest bits?