In 3-dimensional geometry, a plane of symmetry is a 2-dimensional flat dividing surface placed such that things on one side are symmetrical (mirror image) to things on the other side.
... author and expert on mythology
March 28 - Werner Bahlsen[?], biscuit[?] producer (+ 1985)
April 3 - Sally Rand[?], dancer (+ 1979)
April 7 - Ralph Bunche[?], ...