For this brief I really wanted to do a more geometric design rather than something organic and flowy. so I started with just block frames stacked on top of each other in blender and then twisted it. The result was something quite double helixy. Due to my lacking of skills and motivation in 3d modelling, the Obelisk was ok, but the tower was extremely patchy with multiple surfaces and I had a lot of trouble preparing the file for 3d printing with shapeways. In the end however, both models were printed with ease for about 15$ each out of plastic and were very quickly delivered.
Next time I would definately make sure that from the begining i was modelling with no overlapping surfaces or holes.