dd = 25; // disc diameter dh = 2; // disc height sw = dd / 5; // slot width xw = 0.25; // extrude width module joiner(){ difference(){ circle(r=dd/2); for(i = [0:7]){ rotate(45 * i) translate([dd/2-sw/2-xw,0]) square([sw+xw*2,dh+xw*2], center = true); } } } linear_extrude(height=dh) for(y = [0:0]){ for(x = [0:0]){ translate([(dd+2)*x+((dd+2)/2*(y % 2)), (dd+2)*y*(cos(30))]) joiner(); } }