I think, the grey areas above the coins, on the top of the window are the two parts of a rampart that split up under the opening of the growing 5 of pentacles tree.
Those two walls aren't regular, some parts are missing because the rampart has been destroyed.
The thin vertical apertures in the walls seem to be four loopholes or arrowslits that allowed defenders to shoot bows from within the rampart. That's the reason why i think it's more a defensive building than a tower (even if a tower can also be a defensive building but, in my opinion, not in this card).
The two parts of the ramparts look like old ruins that the vegetation has reconquered and the V seems to be a bridge between them, as if some old resistances still remaining.
Obviously, what the rampart used to protect doesn't exist anymore (yellow color fills the area between the two walls). Maybe it was old principles, habits, ideas, all out of date and that would explain why the two characters in the card are grieving and struggling for their existence. They have difficulties moving forward and adapting to change.
The two persons may have been living behind the rampart, fighting to save their comfort and routine, or outside the rampart, trying to destroy it and make things change and improve them. In both cases, they have lost a lot : being poor people and/or being renegades.
Finally, about that window, the main idea seems to be that you can do your best to prevent things from changing, life will always find a way to shake your existence up (the growing and wealthy tree that rocks the wall from its basis).
In the card, changes didn't come from before the rampart but from under it. It's an inner revolution. Revolution often brings a period of chaos and loss but you must surpass it and follow a new path. This is exactly what the two characters are doing. Even if they seem in despair, they are moving somewhere and don't stay stuck in a place by complaining and waiting for better times.
