The images in this set are named pic51.tif to pic511.tif. The numbers start
with 5 to indicate that pic51.tif was taken in the same location as pic5.tif
in set1. All 11 images in this set were taken at regular intervals, two railings
stones apart. The last image (pic511.tif) happens to fall just one and a half
railing stones short of the position of pic6.tif of set1.