$fn=100;

union(){
    difference(){
        union(){
            linear_extrude(height=5, scale=0)
                circle(d=70);
            translate([0,0,50])
                linear_extrude(height=5, scale=0)
                    circle(d=30);
            translate([0,0,100])
                linear_extrude(height=5, scale=0)
                    circle(d=30);
            translate([0,0,150])
                linear_extrude(height=5, scale=0)
                    circle(d=30);
        }
        rotate([0,0,120])
    translate([0,0,-5])
        linear_extrude(height=180)
            polygon(points=[[2.5*cos(60),2.5*sin(60)],[2.5*cos(60)+80,2.5*sin(60)],[2.5*cos(60)+80*cos(120),2.5*sin(60)+80*sin(120)],[2.5*cos(60),2.5*sin(60)]]);
rotate([0,0,240])
    translate([0,0,-5])
        linear_extrude(height=180)
                polygon(points=[[2.5*cos(60),2.5*sin(60)],[2.5*cos(60)+80,2.5*sin(60)],[2.5*cos(60)+80*cos(120),2.5*sin(60)+80*sin(120)],[2.5*cos(60),2.5*sin(60)]]);
rotate([0,0,360])
    translate([0,0,-5])
        linear_extrude(height=180)
            polygon(points=[[2.5*cos(60),2.5*sin(60)],[2.5*cos(60)+80,2.5*sin(60)],[2.5*cos(60)+80*cos(120),2.5*sin(60)+80*sin(120)],[2.5*cos(60),2.5*sin(60)]]);
    }
    cylinder(d=5,h=151);
}