An articulating frame comprising parallel aligned base frame elements (2A, 2B) in a first plane adjustably connected to parallel aligned upper frame elements (4A, 4B) in a second plane, parallel to the first plane, the adjustable connection between any pair of connected base frame (2A, 2B) and upper frame (4A, 4B) elements comprising one or more knuckles (10A, 10B, 10C, 10D) each knuckle being capable of a combination of rotational and linear movement and operable independently of the others to provide both linear and rotational repositioning of a frame element (2A, 2B 4A, 4B) relative to the other of the connected pair at the point of connection.
