$fn=60;

	union(){
		difference(){
			translate([-20,-40,0])cube([40,60,5]);
			translate([0,5,-7])cylinder(r=8.5,h=20);
#			translate([10,-30,-2])cube([4,20,10]);
#			translate([-14,-30,-2])cube([4,20,10]);
		}	
	}