Abstract: A machine for automatically marking a tire tread pattern on a model block or blank prototype tire having a cylindrical-curved surface of a progressively decreasing radius. A plurality of model blocks or a blank tire is mounted on a turntable which rotates at a predetermined constant speed. A laser beam emanating from a laser in a predetermined series of pulses following a raster approach is directed by optic assemblies against the slowly rotating curved surface to form a series of dots which define the tire tread pattern. The laser is pulsed by a computer which stores the tire tread pattern and interprets the pulses from a rotary encoder. One of the optic assemblies moves vertically to have the laser beam scan the curved surface and another optic assembly moves horizontally to keep the laser beam in focus by following the crown or surface curvature. A raster is traced by the laser beam on the curved surface with a raster line denoting one cycle or convolution of the helix.