difference() {
    cube ([60,45,1]);
    
    translate([3,5,0])
        cube ([25,3,1]);
    translate([32,5,0])
        cube ([25,3,1]);
    
    translate([3,13,0])
        cube ([25,3,1]);
    translate([32,13,0])
        cube ([25,3,1]);
    
    translate([3,21,0])
        cube ([25,3,1]);
    translate([32,21,0])
        cube ([25,3,1]);
    
    translate([3,29,0])
        cube ([25,3,1]);
    translate([32,29,0])
        cube ([25,3,1]);
        
    translate([3,37,0])
        cube ([25,3,1]);
    translate([32,37,0])
        cube ([25,3,1]);
}
translate([25,45,0])
cube ([10,2,1]);

translate([25,-2,0])
cube ([10,2,1]);