Has anyone found evidence of a picture of a foot, on Mars? Or a hand? I know the US space program drew a penis on Mars with rover tracks, but that was recent - we would be looking for something older.
That would be more persuasive than a human type "face", because we see human faces in everything - the paneling on the closet door, the clouds in the sky. There's probably even a book or two on that topic - certainly a lot of magazine articles and the like: http://www.dailymail.co.uk/femail/article-3280816/What-photos-s-faces-suffer-facial-pareidolia.html
That would be more persuasive than a human type "face", because we see human faces in everything - the paneling on the closet door, the clouds in the sky. There's probably even a book or two on that topic - certainly a lot of magazine articles and the like: http://www.dailymail.co.uk/femail/article-3280816/What-photos-s-faces-suffer-facial-pareidolia.html