This is what I call a "balcony ladder". It is similar to the library ladders of old.
The hinge is made from 2" brass rail parts. The steps are held in place with 1/4" solid brass dowel that is threaded on the ends and fastened by brass acorn nuts with a solid brass knob backplate as the washer.
The ladder legs are 5/4" popular that have been band sawn to create the bow. The steps are mortised into the legs.
When not in use, a piano hinged shelf on the opposite wall flips up, and after the ladder is above it, drops down to support the ladder for horizontal storage. When people see it in this position the "Wow Factor" kicks in big time. A pulley system could be constructed using 1/4" sash cord and pulleys to support it from the ceiling instead of using a shelf.
The braces below 3 of the steps are intended to minimize racking - 3 sets seems to be the optinum number. They are not nesessariy meant to support weight - although they do.
Please note this is a repost of a reply I made to a post in General Woodworking and Power Tools - I felt it more appropriate in Woodworking Projects.