anchor: love.physics.newRectangleShape
  Shorthand for creating rectangular PolygonShapes.
  
  By default, the local origin is located at the '''center''' of the rectangle as opposed to the top left for graphics.
  shape = love.physics.newRectangleShape( width, height )
  width number The width of the rectangle.
  height number The height of the rectangle.
  shape PolygonShape A new PolygonShape.
  shape = love.physics.newRectangleShape( x, y, width, height, angle )
  x number The offset along the x-axis.
  y number The offset along the y-axis.
  width number The width of the rectangle.
  height number The height of the rectangle.
  angle (0) number The initial angle of the rectangle.
  shape PolygonShape A new PolygonShape.