$fn=100;

difference() {
    cylinder(h=30,d=26,center = true);
    translate([0,0,-3]) cylinder(h=30,d=23.2,center = true);
    translate([0,12,-17]) cube([14,14,30],center = true);
    translate([0,12,-2]) rotate([ 90,0,0]) cylinder(h=18,d=14,center=true);
}