The standard buttonhole is loose on the sides and not sturdy. The Tulips Buttonhole by TechKnitter is beautiful, firm all around, and a very desirable buttonhole.
This buttonhole, invented by TechKnitter, can be done over 2 or more stitches.
It creates a strong buttonhole with matching cast-on and bind-off edges that has uniquely strong sides.
You will need a crochet hook and a small double-pointed needle for this bind-off.