The University of Arizona has a new online geologic teaching tool showing rock structures in interactive 3-D format, using the collection of geosciences professor George Davis.
Using your cursor, you can rotate the samples around for 360-degree views.
[right, screenshot of the new web site, showing a mudstone with folded layers from Tucson Mtns, Arizona. Lower Cretaceous Amole Arkose Formation, ~120 Ma.]