$fn = 180;

difference() {
    union() {
        difference() {
            union() {
                cylinder(d=60, h=20, center=true);
                translate([0,0,-15-10])
                    cylinder(d2=60, d1=25, h=30, center=true);
                translate([0, 0, -7.5-40])
                    cylinder(d=25, h=15, center=true);
            }
            union() {
                cylinder(d=50, h=20.01, center=true);
                translate([0,0,-15-10])
                    cylinder(d2=50, d1=16, h=30.01, center=true);
                translate([0, 0, -7.5-40])
                    cylinder(d=16, h=15.01, center=true);
            }
        }

        for(angle = [0, 90, 180, 270])
        rotate([0, 0, angle])
            translate([0,30,0])
                rotate([90,0,0])
                    cylinder(d=15, h=20, center=true);
    }
    
    for(angle = [0, 90, 180, 270])
        rotate([0, 0, angle])
            translate([0,30,0])
                rotate([90,0,0]) {
                    cylinder(d=5, h=20.01, center=true);
                    translate([0,0,-5]) {
                        cylinder(d=6.25, h=10.01, center=true);
                    }
                }
}