It is not really a hard design, it just looks it.
If you understand the x y z axis, I will try to explain the principle.
Draw a circle in the x y plane
Change view to x z plane, change axis to suit making it a new x y plane.
Copy the circle already drawn in the same place which now looks like a straight line.
Rotate this new circle
70.5288°. from the origin, which is the center of the circle.
Go back to original view with original x y plane.
Pick the new circle which looks like an oval, and either make an array with three copies or copy in place and rotate the new circle 60 degrees twice.
This will give you a line drawing in 3D
Depending on what software you are using and what type of band you require, you can now create the profile of the band. In sketchup it is the 'followme' command.
This band could have been created with the first circle.
Hope you understand this.
I think I have it worked out thanks to 'Magic' with the correct angle of 70.5288°