CNET reports that the Russo brothers, directors of Avengers 4, tossed a Where’s Waldo-style challenge onto Instagram and Twitter.

“Look hard… ” Joe and Anthony Russo teased in the caption to a black-and-white photo of what appears to be Joe Russo sitting in a chair and looking at his laptop in the middle of an unfinished set. For some of us, that’s no clue at all, but naturally, plenty of devoted fans saw more than that.

The general consensus on social media seems to be that there are letters hidden in the photo, but no one could agree on what exactly they spell. “Avengers: Endgame” was one popular nomination, playing off a line spoken by Doctor Strange in Avengers: Infinity War.

One Twitter user has his own suspicions as to what the cryptic message means.

Or…

Hmmm…is filming confirmed? What do you think? Tell Nerdbot in the comments!