$fn=25;
pegtext="CUBE";
pegtext1=["C","U","B","E"];
pegtext2=[["S","C","A","D"],["O","p","e","n"]];
difference()
{
    cube([31.80,15.80,9.60]);
    translate([1.45,1.45])
    cube([28.90,12.90,8.60]);
}
translate([3.90,3.90])
    for (j=[0:1]){
        for (i=[0:3]){
            
            translate([i*8,j*8,9.60]){
            cylinder(h=1.80,r=2.42);
            translate([0,0,1.8])
                linear_extrude(.4)
                    text( pegtext2[j][i], .8, halign="center", valign="center");
        }
    }
}
translate([7.90,7.90])    
    for (k=[0:2]){
        translate([k*8,0])
        difference()
        {
            cylinder(h=8.60,r=3.25);
            cylinder(h=8.60,r=2.40);
        }
    }