Hint 1
Our xenosymbologists hypothesise that the aliens might be trying to label what lies in those locations.
Hint 2
Whatever could the aliens be trying to use nitroglycerine for? Perhaps they’re trying to rescue whatever’s strongly bound together inside the dairy and egg farm.
Hint 3
It seems like these aliens have different ways of drawing chemical molecules on their home planets. Wonder if their life forms are based on the same building blocks as terrestrial creatures?