San Pietro Di Castello
Venice: Castello District
Synapses
Hint: In the lower right there are a number of x-rays of the brain with the number 5 and then symerian symbol for 1. Line up 5 with that symbol on the dial. On the second picture from the left is a mathematical progression, starting with the sumerian symbol for 1 and continuing with "+2+6+2+1..." and so on. This is the system in which the codewheel is arranged. As you can see on the code wheel, the symbol following the Sumerian 1 is the Sumerian 3 (being 1+2), the next is the Sumerian 9 (being 3+6), then Sumerian 11 (9+2) and Sumerian 12 (11+1). Continuing the sequence will let you figure out which Sumerian symbols are missing on the codewheel (17 and 31).
Once that portion is done, it's a nice an easy photohunt where you guide the symbol over the thick blood vesseles, turning them blue.