side=40;
material=2;
kerf=0.05;
thickness=material+2*kerf;
difference()

{
    circle(side/1, $fn=3, 
   true);
    square([side+40,thickness],true);
    square([thickness,side+8],true);
}


square(side/2,true);


translate([65,0,0]){
difference ()
{
circle(side/1, $fn=3, 
   true);
    square([side,thickness],true);
    square([thickness,side+8],true);
 
}

square(side/2,true);}


translate([130,0,0]){
difference ()
{
circle(side/1, $fn=3, 
   true);
    square([side-9,thickness],true);
    square([thickness,side+8],true);
 
}

square(side/2,true);}

translate([195,0,0]){
difference ()
{
circle(side/1, $fn=3, 
   true);
    square([side+40,thickness],true);
    square([thickness,side-9],true);
 
}

square(side/2,true);}