A display system comprises a projector combined with a retro reflective screen and a viewer distance from the projector such that the observation angle is less than approximately 2-3 degrees. The wire is fed into the flame by aligning the cast-plane of the wire with the flame-jet by using a tubular member formed into a circular shape to provide sufficient length to guide wire and to provide the necessary twist amount to the wire to align the cast-plane with the axis of the flame-jet. The comparators are connected to a decision circuit which outputs to a control circuit a signal instructing a normal state until the feedback signal reaches the control voltage, and thereafter a signal instructing a normal state or a stand-by state that is instructed by the switching instruction signal. Thus, the blocks of data are copied only into the most recently created image within the repository.