Have anyone thought any more on the Margherita conundrum? Surely there must be a sign there.
The closest pizza place to the SI office is the Slice Club (there are closer ones but they were closed on Tuesday). Margherita is the second item on Slice Clubs menu behind the Cheesy Garlic Bread). All their pizzas are 18".
2 = Beta in greek.
18" = 18th of October.
Beta today is confirmed.