$fn=100;
 
width = 30;
radius = 19;
cyl_radius = 8;
t = width/2;
 
// Cube
translate([0,0,0]) 
difference() {
    cube(width, center=true);
    sphere(radius);  
}
 
 
translate([0, 0, -t]) 
   cylinder(h=width, r=cyl_radius); 
 
translate([-t,0,0])   
   rotate (a=90,v=[0,90,0]){
   cylinder(h=width, r=cyl_radius);
} 
 
translate([0,t,0])   
   rotate (a=90,v=[90,0,0]){
   cylinder(h=width, r=cyl_radius);
}