I will start by saying that this is NOT an original idea - I've seen it somewhere.
Make a blue foam master of a hexagonal column, make it as accurate as possible.
Make latex moulds of sections of the columns - anywhere between 3 - 8 inches long.
Make plaster casts using the latex moulds, then distress each of the sections and vary the height. (You should be easily able to cut these sections with a standard saw).
Glue to a baseboard with uPVA glue and paint.
Tony
http://dampfpanzerwagon.blogspot.com/