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.
