Manoeuvrable Ladder

I was so impressed by Iceng's excellent Magic Rolling Steps Instructable, that I immediately thought I'd improve on the idea by adding castors.  This is the prototype, but castors could also be used on a full-size extending ladder to allow you to easily manoeuvre it close to the wall to get the ideal 15 degree angle.  The safe angle for a ladder is to position it one foot away from the wall for every four feet of ladder's height before you climb it.  Safety first, chindogu.