protected override void Render(ContentWriter cw, Vector2D offset)
{
var top = offset + new Vector2D(Size.X / 2, Size.Y);
var left_topleft = offset + new Vector2D(Vector1D.Zero, Size.Y * 3 / 4);
var left_bottomleft = offset + new Vector2D(Vector1D.Zero, Size.Y * 1 / 4);
var right_topright = offset + new Vector2D(Size.X, Size.Y * 3 / 4);
var right_bottomright = offset + new Vector2D(Size.X, Size.Y * 1 / 4);
var bottomright = offset + new Vector2D(Size.X, Vector1D.Zero);
var indent = Size.X / 5;
var bMidR = offset + new Vector2D(Size.X - indent, Size.Y / 10);
var bottommid = offset + new Vector2D(Size.X / 2, Size.Y / 10);
var bMidL = offset + new Vector2D(indent, Size.Y / 10);
cw.MoveTo(offset);
cw.LineTo(left_bottomleft);
cw.CurveFromTo(left_topleft, top);
cw.CurveFromTo(right_topright, right_bottomright);
cw.LineTo(bottomright);
cw.CurveTo(bMidR, bottommid);
cw.CurveFromTo(bMidL, offset);
cw.CloseShape = true;
}