Abstract: A phase shifting projector includes an incandescent lamp, a heat-absorbing filter filtering infrared light from the incandescent lamp, a condensing lens receiving light from the filter, a transparent slide having a sinusoidal grating thereon, a projecting lens, a rotatable transparent plate disposed between the slide and the projecting lens, a test surface on which the grating is projected, and a stepper motor connected to the transparent plate for rotating it about an axis generally parallel to a line of the grating to modulate the phase of the grating image projected on the test surface.

Abstract: This invention is directed to a synthetic fireplace log with a hollow core, said log being composed of shredded paper and wax. The logs are produced by continuously compacting shredded paper into one end of a compaction chamber, injecting hot molten wax into the compacted paper in the compaction chamber, cooling and hardening the wax, and continuously extruding finished logs from the opposite end of the compaction chamber with means for cutting the continuously extruded log into convenient lengths.