difference() { translate([0,11-8.8,0]) difference() { cube([26,22,7],center=true); translate([13.5,4,0]) cube([20,20,8],center=true); translate([-13.5,4,0]) cube([20,20,8],center=true); } translate([0,10,0]) cylinder(r=1.7, h=40, center=true, $fn=30); cylinder(r=1.7, h=40, center=true, $fn=30); translate([7.5,0,0]) rotate([90,0,0]) cylinder(r=1.3, h=40, center=true, $fn=30); translate([-7.5,0,0]) rotate([90,0,0]) cylinder(r=1.3, h=40, center=true, $fn=30); }