#17 those look impossible to skate in, the fact that skates need to be tied snug enough around the ankle to keep the blade perpendicular to ankle to prevent the ankle from bending over and possibly braking
It’s not the zipper in a modern sense, but still a fastener for a purse or small handbag. It consists of an expandable frame with loops, stretching when you open your purse and shrinking when you close it.
#17 those look impossible to skate in, the fact that skates need to be tied snug enough around the ankle to keep the blade perpendicular to ankle to prevent the ankle from bending over and possibly braking