The instant invention discloses a receptacle having a shape along the
width of its face that is flat in one plane and along its length that has
a constant radius. The shape of the face of the receptacle allows for the
proper seating of an inserted plug. The shape of a wall plate around the
receptacle along a section which runs along its vertical axis defines a
surface of positive first differential and zero second differential,
includes a combination of splines drawn between points of varying
distance from a datum plane. The surface has zero second differential
when the rate of height increase of individual splines is constant. When
ganged with a switch, the front surface of the switch follows the shape
of the cover plate.