http://cgi.ebay.com/ws/eBayISAPI.dll...tem=2187110696

Chicago Architecture, presented by The Art Institute of Chicago. Date unknown. The box is
scratched and dented and a little squashed, but the contents remain in mint condition.

However, the collection is incomplete, the box indicates that there are 20 note cards and
envelopes in the complete set. There are 3 cards missing from a full set - although all
four different designs are still represented (and there's still 18 envelopes!)