The Magic Guessing Ends Domino Trick

Ask a volunteer to layout facedown a set of dominoes in a straight line with the condition that each tile end is adjacent to another tile end with matching suits as in a standard game of dominoes. Leave the room while they do this.  You then return and magically announce the suit values on either end of the line of facedown dominoes.

All you have to do is first secretly remove a tile from the set with two differing suit ends.  It is these two suits that must be the values of the ends of the layout, because a complete set would link back to itself if arranged in a sequential circle.  Note, the trick doesn't work if you remove a double.

www.domino-play.com/Magic.htm