#local P1 = 0.3;
#local P2 = 0.6;

#declare torbogen =
    union {
	prism {
	    bezier_spline 
	    -125, 125,
	    24
	    <-450, 0> <-450*P2, 720> <-450*P1, 720> <0, 720>
	    <0, 720> <450*P1, 720> <450*P2, 720> <450, 0>
	    <450, 0> <420, 0> <390, 0> <360, 0>
	    <360, 0> <360*P2, 570> <360*P1, 570> <0, 570>
	    <0, 570> <-360*P1, 570> <-360*P2, 570>, <-360, 0>
	    <-360, 0> <-390, 0> <-420, 0> <-450, 0>
	    texture {
		pigment {
		    color <0.7, 0.7, 0.75>
		}
	    }
	    rotate <-90, 0, 0>
	    rotate <0, 90, 0>
	}
	sphere {
	    <0, 570/2, 0> 350/2
	    texture {
		pigment {
		    color <1, 1, 1.5>
		}
	    }
	}
    }