use <library.scad>a = 10.16;d = 1.6;thickness = 2;translate([0,a,0]){hole(a,d,thickness);}translate([0,-a,0]){hole(a,d,thickness);}for(i=[0:5]){translate([a*i,0,0]){hole(a,d,thickness);}}module hole(a,d,thickness){difference(){translate([0,0,thickness/2]){cube([a,a,thickness],center=true);}translate([0,0,thickness/2]){cylinder(h=thickness*2,r=d,$fn=100,center=true);}}}