def brace(w, h)
      raise(ArgumentError, 'width must be != 0') unless w != 0
      raise(ArgumentError, 'height must be != 0') unless h != 0

      path("M0,0 Q#{w},0 #{w / 2.0},#{-h / 4.0} T#{w},#{-h / 2.0}" \
           "Q0,#{-h / 2.0} #{w / 2.0},#{-(3.0 * h / 4.0)} T0,#{-h}")
    end
def brace(w, h)
      raise(ArgumentError, 'width must be != 0') unless w != 0
      raise(ArgumentError, 'height must be != 0') unless h != 0

      path("M0,0 Q#{w},0 #{w / 2.0},#{-h / 4.0} T#{w},#{-h / 2.0}" \
           "Q0,#{-h / 2.0} #{w / 2.0},#{-(3.0 * h / 4.0)} T0,#{-h}")
    end
(w,h) - width & height of rectangle enclosing brace.
 Normally the brace is drawn with its opening to the
 left and its lower point on the origin.

 Set w < 0 to draw right-opening brace. Set h < 0 to
 position top point at origin.

 The placement & orientation is affected by the
 current user coordinate system.