Custom Hinge Selection Tool
Holes : Squares, Stars and More
There are many other different perforations that can be done on a hinge, and depending on tooling available, tooling that can be created, or laser cutting machinery, almost any shape or size can be done.
Some options are keyhole slots, squares and more.

Stars

Keyhole slots

Square

Spotface
Two rare options are a spotface, where an indentation is made around a hole to make room for a washer or insulator, and a breakthrough hole where the material is left jagged for mounting the hinge to cardboard or cloth.

Breakthrough hole
