This Sapiens promo contains a set of 8 double-sided tiles that show each of the 8 scenes in the base game on both ends of the tile.
Before the beginning of the game, shuffle the 8 double tiles with the base tiles. Then, during setup, remove 8 tiles in addition to the normal number removed (so 20 tiles for 2 players, 26 for 3 players, and 14 for 4 players).
On Your Turn
During the game, treat double tiles just like normal tiles. Each offers the same scene twice.