#declare treibstofftank = 
    union {
	sphere {
	    <0, 3.8, 0> 
	    0.5
	}
	cylinder { 
	    <0, 3.8, 0> 
	    <0, 0.5, 0> 
	    0.5
	}
	sphere {
	    <0, 0.5, 0> 
	    0.5
	}
	pigment {
	    rgb <1, 0.5, 0>
	}
    }