Ahead of the release of Assassin's Creed 3, Ubisoft is hosting a mysterious online puzzle game for eagle-eyed fans of the series.
Three historical American Revolution paintings published on assassinscreed.ubi.com have each been expertly doctored to include one tiny secret.
If users spot the anomaly and click on it, they will unlock an individual pixel on a fourth and final mystery image - the purpose of this final painting is not yet known, though Ubisoft has said something special will happen.
However, for the fourth image to be cleared of all pixels, enough people need to discover the mysteries of each of the three paintings.
The secret of the first painting, which depicts the death of general warren at the Battle of Bunker Hill, has already been discovered by enough people. The second painting, however, is only half way there.
To give you an idea of how subtle Ubisoft is playing this game, below is the first image, and beneath that we're highlighting its secret.
Here's the original
And the secret (yes it's a piece of Eden)
The next painting can be found at assassinscreed.ubi.com - this one's just as hard to spot.
Best of luck!