Have there ever been messages across puzzles?

Apologies if this has been asked before but I was just wondering if the puzzle makers ever put messages across multiple puzzles using the shapes of the puzzles?

I figure because of the nature of the piece shapes and the limited space, there are only so many shapes you can form. Thus the creators default to making simple recognisable shapes like letters, numbers and emoticons. Was just wondering if the creators ever put little messages across the puzzles.