$fn = 200;

cube([40,30,2]);
difference(){
    translate([0,0,15]){
        cube([40,30,2]);
    }
    translate([25+5+2,5+2,15]){
        //cube([5,5,2]);
        cylinder(h=2,r=3);
    }
    translate([25+2.5,20,15]){
        cube([7,5,2]);
        //cylinder(h=2,r=2.5);
    }
}

cube([40,2,15]);
translate([0,28,0]){
    cube([40,2,15]);
}
difference(){
    cube([2,30,15]);
    translate([0,7.5,4.5]){
        cube([4,15,6]);
    }
}
translate([2,2, 22]){
    cube([2,26,13]);
}
translate([0,0, 20]){
    cube([2,30,17]);
}