$fn=48;

translate([-2.5,0,0])
cube([25,10,10], center=true);
translate([-7.5,0,10])
cube([5,10,10], center=true);
translate([-12.5,0,5])
cube([5,10,10], center=true);
translate([-10,0,10])
rotate([90,0,0])
cylinder(r=5, h=10, center=true);
translate([10,0,5])
cylinder(r=5, h=20, center=true);
translate([7.5,0,10])
cube([5,10,10], center=true);
translate([5,2.5,10])
cube([5,5,10], center=true);