An abstract photograph of a sandstone water erosion resembling a spine imprint taken at Terrigal. This simple photograph is quite fascinating and I have an A3+ framed print of it at home. Depending on the time during the day the erosion holes seem to turn from convex to concave. This optical illusion must have something to do with the shading of the impressions. By the way the real state is concave in case if you are wondering.