Friends: The ‘one thing you never noticed about Monica’s apartment' is either proof of the multiverse or just bad continuity

Because Friends is a bottomless source of trivia, and when the Earth is swallowed by the Sun in billions of years people will still be learning tidbits about Chandler, there is a fresh ‘one thing you never noticed’ story going around this week.

It’s well known that Monica lives opposite Ugly Naked Guy - but wait! It seems she is also neighboured by shape-shifting buildings a la Inception.

Here’s the evidence:

The view from both windows clearly alternates between open vista of other buildings and brick wall.

What can we learn from this? Either:

That Friends takes place in a number of parallel universes, each slightly different.

Or

In the early seasons, the continuity/set design people probably never envisioned the show would be so big that people would be picking out such tiny details more than a decade after it finished.