Abstract: An electromagnetic projectile launcher is provided with a firing switch which alternately opens and closes to repeatedly commutate current from a high current supply to a pair of projectile launching rails. A rotor having a transverse conducting element is rotated within and moved axially along a cylindrical stator. Brush members which have widths which decrease in an axial direction along the stator are shorted by the conducting element between shots for varying lengths of time as the rotor travels axially along the stator.

Abstract: A viewing port for doors such as residences including a light polarizing assembly including at least two linear polarized optical elements, one mounted for rotation with respect to the other element(s) to change the viewing port from light passing to light blocking or reduced transmission condition. The light polarizing assembly is located at the inner side of the door and is surrounded by a tapered portion of its mounting toward the outer face to provide undistorted wide angle viewing of the area surrounding the door. In another embodiment of this invention, my viewing port is designed to be integrated into a stained glass window.