Here is a 3-D view of 2 and a half periods of the DNA molecule. You can view the stereograph by:

1. Using the Cross-Eyed method.
2. Using 3D prism glasses (berezin.com/3d/3dprism.htm)
3. Using Brian May’s OWL Stereoscope (londonstereo.com)

I put together the 3D model from a Cochrane’s of Oxford kit, and Dr. Brian May created the stereograph.