In 1972, Iran issued a stamp and souvenir sheet to commemorate the 1972 Olympic Games. One of the six stamps in the set and on the souvenir sheet depicts an archer atop a rook on a chessboard shooting in the direction of a black knight.
The block of four should appear in the window below. Here is the souvenir sheet. The scan shows the watermark, a large lion in a circle as well as arabic text.
Click the following to see a close up of the watermark.
Click here to view a close up of an inverted watermark.
About a year ago, I had the opportunity to pick through more than a dozen of these souvenir sheets. Living proof that you should always be on the lookout for printing vaieties. Here are two that I found.
Click here to view a close up of a printing shift to the right.
Click here to view a close up of a printing shift to the left.
These two first day covers have the same cachet commemorating the 1972 Olympic games. Note the postmarks are black and purple.
Here is a different cachet, and the same black and purple postmarks on the set and the souvenir sheet.
Affordable Foreign Errors: On Postage Stamps of the World, Paul S. Greenlaw, Martin Sellinger (Editor).