Abstract: An apparatus for forming visible lines on a surface on a temporary basis comprises at least one laser which is directed at phosphors provided in or on the surface and means for controlling the laser to cause it to sweep the area on which the lines are to be marked. Optical deflectors are provided for guiding the laser beam. A first method of forming such lines comprises sweeping the surface incorporating the phosphors and on which the lines are to be marked with at least one laser beam. In a second method, the area is again swept by the at least one laser beam and, after the phosphors have been activated, each laser beam is deactivated and the phosphors are stimulated by flood radiation. Such phopsphorescence can then be quenched at a desired time.

Abstract: A wafer having microelectronic circuit chips thereon having electrical connections between the chips arranged so that effectively the chips are on a surface which at least in one direction is unbounded. The electrical connections may be arranged so that the chips are effectively on the surface of a cylinder, or they may be effectively on a helix. The electrical connections may optionally be arranged so that the chips are effectively on a toroid, or on an endless helix. The output connections from a chip adjacent one edge of the wafer may be connected through electrical conductors direct to the input connections of a chip adjacent the opposite edge of the wafer.