Regardless of origin, the fact is that mobiles can be fascinating pieces of art. Unlike most other forms, they're three-dimensional rather than two, and unlike all other forms, they're built to move in response to air currents. This makes a mobile with even a few independent parts an object of infinite views, and to me can elicit the same fascination and infinite musings as watching a real log fire on a cold winter night. No matter how long you look, you never want to look away for fear that you will miss whatever unique composition will appear next.
The Calder mobile at the top of this post is titled National Gallery III [maquette], 1972 and hangs in the Washington National Gallery. The image was taken from calder.org, the Web site of the Calder Foundation. The birds mobile is included, with detailed instructions for its construction, in the book Magnificent Mobiles by Melanie Williams, (c) 1994, Quintet Publishing Limited.