Extruding Ice from Steel Fences and Pipes with Diurnal Freeze/Thaw (2008)
Pretty cool.  I don't ever remember seeing this occur anywhere.  More examples of this occurring in nature on his main page: <a href="http://my.ilstu.edu/~jrcarter/ice/diurnal/" rel="nofollow">http://my.ilstu.edu/~jrcarter/ice/diurnal/</a>