Reason for mysterious letters revealed

In this photo made on Tuesday, Dec. 1, 2009, Michael Tolson, a conceptual artist who goes by the name tENTATIVELY, a cONVENIENCE, or Tent for short, shows one of the pieces of mail he received at his home in the Polish Hill neighborhood of Pittsburgh. Tolson received two pieces of mail at his house on Nov. 24. with no return addresses, six cents postage due on one. One contained this small saucer. "Congratulations to Michael Tolson for everything you've achieved so far,'' written on the front; "Well done, Michael + Lenka,'' on the back. Nearly every residence in the city's Polish Hill neighborhood received letters, 620 in all, as part of a project by artists Michael Crowe and Lenka Clayton. (AP Photo/Keith Srakocic)

December 2, 2009 6:06:43 PM PST
Two pieces of mail arrived at Michael Tolson's house on Nov. 24. Neither had a return address.