side=40;
material=2;
kerf=0.05;
thickness=material-2*kerf;
$fn=120;
difference()
{
    circle(side/2, true);
    square([side,thickness],true);
    square([thickness,side],true);
}

square(side/2+1,true);



translate([0,50,0])
{
    difference()
    {
        circle(side/2, true);
        rotate([0,0,90]) translate([0,side/2,0])  square([thickness,side/2],true);
        rotate([0,0,-90]) translate([0,side/2,0])  square([thickness,side/2],true);
        rotate([0,0,0]) translate([0,side/2,0])  square([thickness,side/2],true);
    }
}

translate([0,100,0])
{
    difference()
    {
        circle(side/2, true);
        rotate([0,0,90]) translate([0,side/2,0])  square([thickness,side/2],true);
        rotate([0,0,-90]) translate([0,side/2,0])  square([thickness,side/2],true);
        
    }
}

translate([0,150,0])
{
    difference()
    {
        circle(side/2, true);
        rotate([0,0,0]) translate([0,side/2,0])  square([thickness,side/2],true);
       
        
    }
}

translate([0,-50,0])
{
    difference()
    {
        circle(side/2, true);
        
         rotate([0,0,0]) translate([0,side/2,0])  square([thickness,side/2],true);
         rotate([0,0,30]) translate([0,side/2,0])  square([thickness,side/2],true);
        rotate([0,0,60]) translate([0,side/2,0])  square([thickness,side/2],true);
    
    rotate([0,0,90]) translate([0,side/2,0])  square([thickness,side/2],true);
    
     rotate([0,0,120]) translate([0,side/2,0])  square([thickness,side/2],true);
    
    rotate([0,0,150]) translate([0,side/2,0])  square([thickness,side/2],true);
        
     rotate([0,0,180]) translate([0,side/2,0])  square([thickness,side/2],true);
        
     rotate([0,0,0]) translate([0,side/2,0])  square([thickness,side/2],true);
         rotate([0,0,210]) translate([0,side/2,0])  square([thickness,side/2],true);
        rotate([0,0,240]) translate([0,side/2,0])  square([thickness,side/2],true);
    
    rotate([0,0,270]) translate([0,side/2,0])  square([thickness,side/2],true);
    
     rotate([0,0,300]) translate([0,side/2,0])  square([thickness,side/2],true);
    
    rotate([0,0,330]) translate([0,side/2,0])  square([thickness,side/2],true);
        
     rotate([0,0,360]) translate([0,side/2,0])  square([thickness,side/2],true);
       
        
    }
}