Window Pain by Stewart Coffin - RARE

Original puzzle from Stewart Coffin, his design #186.  The last time one was up for auction was in 2009!  

Description
This puzzle consists of six polyomino pieces and a two-sided tray.

Goals
Problem 1: Assemble the pieces on this side to form a 5x5 square. There are 12 solutions. How many can you discover? One is shown: (see photo)
Problem 2: Now turn the tray over and assemble any or all of these solutions on the other side, making use of both the top opening and the side slot. All 12 are possible. For a starter, try the one shown above.
Problem 3: Assemble without using the side slot. Difficult - there is only one way.
Problem 4: Assemble using ONLY the side slot. Most difficult - again there is only one way.

The puzzle is located in the United States, but I will ship worldwide.
Customs forms for international shipments will reflect actual payments.
Payments can be made through PayPal (Friends & Family preferred).
Buyer to pay shipping calculated after auction
Buyer may choose supplemental insurance at their expense.
Please wait for the updated invoice before making payment.