How has the artist used light to create a desired affect in this piece? what do you hypothesize the source of the light to be and why?

The artist has used light to direct the eye's attention toward the figures sitting at the tables. Although we cannot see the source of the light, based on prior knowledge we can guess that the light is coming from a window, The window is higher than the people because the light is being cast downwards.

Explanation:

i came across this and i found it funny that when you're bored you play hangman on so im going to guess a : )