Raiders of the Lost Ark
1981

In this painting Drew signed the picture two ways: with his name and with the logo representing an 'S' (for Struzan) in a rectangle.  By using both he linked the mysterious logo he had been using to his name.  By doing so Drew finally solved a mystery for many admirers and collectors that had baffled us for years.  It was one of the last times he used that logo. The reason for the logo in the first place turns out to be interesting in itself.  Drew had always signed his pictures with the simple 'Drew'.  The movie industry would remove his signature from the painting when it was being printed.  The inane explanation was that the word was distracting from the message.
So Drew designed a logo which was simple en inexplicable enough to get lost within the picture.  That's why so often he would actually hide it.  As his reputation and popularity grew he found they actually wanted his signature on the work.  Seems now that his name gives credibility to a movie and they want to be able to see it, even sending art back to be signed when he forgets to sign it.
By the way, this isn't the original '81 one sheet, it's the tenth anniversary reprint.