A well-executed theorem can be quite pricey, but I stumbled upon this little gem for a mere 35 dollars at Antiques at Narrowfellow:
Measures about 8 by 8 on cream-colored velvet. Dated '85, which I guess could easily mean 1985. But regardless of its age, there's no arguing with its charm. It would be doubly sweet in a vintage frame.
Snap it up now!