$fn=100;

difference(){
    translate([0,0,0])sphere(4,5,5);
    translate ([-10,-10,-0.3])cube([20,20,0.7]);
}

translate ([0,0,-2.5])cylinder(5,0.5,0.5);

difference(){
    translate([0,0,-0])cylinder(0.2,7,6);
    translate ([0,0,-0.5])cylinder(5,0.6,0.6);
}
difference(){
    translate([0,0,-0.19])cylinder(0.2,6,7);
    translate ([0,0,-0.5])cylinder(5,0.6,0.6);
}