This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
Ordinary hinges can be easily bent and so placed on posts that a gate can be swung in either direction. As shown in the illustration, hinges can be made to fit either round or square posts. The gate half of the hinge is fastened in the usual way. The post half is bent and so placed that the hinge pin will approximately be on a line between the centers of the posts. The gate and post should be beveled off to permit a full-open gateway. - Contributed by R. R. Schmitz, Birmingham, Ala.
Ill: The Post and Gate are Cut Away Back of the Hinge to Allow the Latter to Swing Back