Abstract: A sign display comprises a plurality of triangular display elements each having three display surfaces. The display elements are arranged along mutually perpendicular sets of axes to define a matrix display having a display plane. Rotary drive shafts extend through the display element parallel to the display surfaces, and each display element includes clutch structure comprising frustoconical clutch members received in frustoconical apertures formed in the display element and spring biased to normally coupled the display element for rotation with the drive shaft extending therethrough. Abutment surfaces corresponding to the display surfaces project from the lower end of each display element, and a stop arm is associated with each display element for selective actuation to terminate rotation of the display element with a predetermined display surface situated in the display plane.