Cubster wrote:So is that how they were constructed then, in concrete layers?
The shuttering used to provide a mould for the concrete leaves an impression of itself in the face of the concrete. If the shuttering was made up of boards say the size of modern scaffold planks that would give the layered effect. You can sometimes even make out the woodgrain in the face of the concrete.
Using plywood for the model is an inspired idea and really pulls off the effect perfectly.