difference()
{
	translate([ -35, -35 ]) intersection()
	{
		union() {
			difference() {
				square(100, true);
				square(50, true);
			}
			translate([ 50, 50 ])
				square(15, true);
		}
		rotate(45) translate([ 0, -15 ]) square([ 100, 30 ]);
	}

	rotate(-45) scale([ 0.7, 1.3 ]) circle(5);
}