cube([3,30,1],true);
translate([0,-15,0]) 
   cube([8,4,1],center = true);
translate([-1.25,-19,0]) 
   cube([1,4,1],center = true);
translate([1.25,-19,0]) 
   cube([1,4,1],center = true);
translate([-3.5,-19,0]) 
   cube([1,4,1],center = true);
translate([3.5,-19,0]) 
   cube([1,4,1],center = true);