One of my highlight acquisitions at the 2009 National in Coralville was this most interesting BT Co Canada pony with a coin impression in the dome. Surprisingly enough, the coin used to make the impression was a 1921 US Lincoln penny! Now that should stir up some interesting speculation as to which side of the border this insulator was made. Any comments??? (embossing index  B.T. Co. OF CAN., blue to blue aqua)
Howard Banks purchased this insulator early on at the show before I had a shot at it, but knew my passion for such oddities and later offered it to me. Thanks again Howard (and Linda) for putting a big smile on this collector's face!
UPDATE April 2013: Due to a rash of recent coin impressions appearing on the market, an investigation has concluded that these are post production coin impressions. Authentic coin impressions made in the mold were compared to those in question and several dissimilarities were found. We are currently trying to determine the source of these by tracing them back to previous ownership. The chain of ownership in reverse thus far for the above specimen is: Dwayne Anthony, Howard Banks, Andy Wadyz, Larry Veneziano & Mildred Veneziano. If anyone has any information of a prior source, please let me know.