This thing was created as a 3D printing test, to see how well your 3D printer did prints without supports and with curves. It was made in OpenSCAD with the following code:
difference()
{
translate([0,-25,0])intersection() { sphere(30); translate([-22,-22,-22])cube(44); }
union() { translate([0,-25,-25]) cylinder(50,15,15); rotate([90,0,0]) cylinder(50,15,15); translate([-3,-25,0])rotate([0,90,0]) cylinder(50,15,15);}
}