I spent some time last weekend trying to figure out how to simulate the stone walls of the canal. I have, of course, the examples from the museum scene reconstructions. The two are quite different, and I really don’t know which may be more correct. Perhaps the only thing that might serve as an example, is the wall at the moat of the Imperial Palace in Tokyo. However, I’ve noticed from looking at photos that even this differs from the stone structure surrounding the gate at the palace grounds.
Meanwhile, I didn’t even have any experience in making a wall for a diorama, so I went on the Internet to look at different ways that people having simulated stone walls for dioramas, some very simple, some very complicated.
I considered making a wall from clay, since I was most familiar with using it, but clay is heavy. I also saw how some modelers use hydrocal to cast stone pieces. But, that requires making molds. Finally, I settled on simply carving plastic insulation foam, as I was using the stuff for my diorama anyway.
For this, I simply drew a pattern on the face of the foam, and I used the end of a small steel ruler to score the foam, which gave the wider-looking gaps between the stones.