// -*- C -*- frameth=0.8; l0= 0.425; l1= 0.25; del=l0+l1*2; for (r=[0,90,180,270]) rotate([0,0,r]) translate([10,-(10+frameth),0]) cube([frameth, 20+2*frameth, 0.4]); translate([-11,-11,0]) cube([2,2, del + l1]); translate([-3,-3, del]) cube([6,6, l1*2]);