shower shelf for 18mm pole

100mm x 60 mm side is 2mm

difference(){
//**************************
union(){
cylinder(20,12,12,center);
difference(){
translate([-52,0,0])
cube([104,64,8]);
translate([-50,2,2])
cube([100,60,8]);
}//DIFFBOX
}//BLOCK add
//*******************************
union()
{
cylinder(21,9.2,9.2,center);
translate([-6,-14,0])
cube([12,8,20]);

}//remove
//********************************
}//diff