#declare Triebwerk_neg =
    merge {
	cone {
	    <400, 0, 0>, 60
	    <350, 0, 0>, 60
	}
	cone {
	    <351, 0, 0>, 60,
	    <300, 0, 0>, 10
	}
	cone {
	    <301, 0, 0>, 10
	    <200, 0, 0>, 10
	}
    }