Glad that MO is up and running again. Following the suggestion by Michael Murray one can also produce more than just one sudden smiley: ![alt text][1] I guess, that a higher number of images is also possible. But probably some structure may be visible from other directions as well in this case. By the way: The problem seems to be a bit related to tomography... [1]: http://regularize.files.wordpress.com/2012/11/suddensmileys.gif