only one follower remaining that can be stationed unless the roads or city are completed to score and return those followers to their stock. In contrast, purple only has one monk follower on the board at [H3] at this time, but that monk is effectively stranded until the end of the game: there is no possible tile that can be played in [I3] as there are only two single-road tiles (with a cloister) and those are already on the board at [H3] and [D5]. However, that monk will score eight points (one for the cloister and seven for the surrounding tiles) at the end of the game. Worse, the green knight follower in [H6] will not score any points and is stranded because the city will never be completed. Yellow has three farmer followers, one knight [J4], and one thief [I5]; both the knight and thief remain active and can be returned by completing that city and road, respectively. Tiles The original board game has 72 tiles with city, field, and road features; the River mini-expansion adds 12 tiles with river features. The version of the game currently in print includes the River and Abbot mini-expansions. The river tiles are used as an alternative to the standard CRFR start tile and have the same dark-colored back to indicate this. The starting river tile is called the source (a river tile with a single river edge) and the final river tile is called the lake (again with a single river edge); players take turns placing all twelve river tiles to start the game, including follower placement and scoring, if relevant, then after the lake river tile has been played, proceed to place the remaining 71 terrain tiles. Nomenclature Kárná used a four-character tile code which described the feature on each edge of the tile as either a road (R), meadow (M, aka field), or city (C), written clockwise from an arbitrary starting edge. For instance, CRMR (modified as CRFR to conform with the terminology of this article) would describe the starting tile, starting from the top edge. With three possibilities for each edge, theoretically there are 81 (=34) possible tile combinations, but as some are duplicates because the tiles may be rotated arbitrarily, there are actually 24 possible combinations. Capaldi and Kolba, professors of mathematics at Valparaiso University, also counted 24 distinct types amongst the 71 non-river tiles of the starting