translate([0, 0, d])
                rotate([0, 90, 0])
                    cylinder(h = le + 2, d = d2, center = true);
        }

        //intersection() {
            translate([10, 0, 0])
                cylinder(h = 100, d = 30);

            translate([-10, 0, 0])
                cylinder(h = 100, d = 30);
        //}
   }

A slightly modified version of Jon's code doesn't preview correctly with OpenSCAD 2016,10,4 le = 10; // length d1 = 25; // diameter of top d2 = 35; // diameter of bottom d = -8; // delta to drop center of bottom $fn = 100; z_offset = -6; module shape() { translate([0, 0, z_offset]) intersection(c) { difference() { rotate([0, 90, 0]) #cylinder(h = le, d = d1, center = true); translate([0, 0, d]) rotate([0, 90, 0]) cylinder(h = le + 2, d = d2, center = true); } //intersection() { translate([10, 0, 0]) cylinder(h = 100, d = 30); translate([-10, 0, 0]) cylinder(h = 100, d = 30); //} } } echo(version()); shape(); F6 gives the correct shape but F5 doesn't unless the extra intersection is enabled. Also the first cylinder should be highlighted but the difference gets highlighted instead. Are these known bugs or should I open an issue?