The "Bis" effect allows the player to duplicate a house number on any street. The new house must be directly adjacent, to the left or right of the house with the same number.

Duplicate houses can never be separated by fences. When duplicating a number, write "bis" next to the number in the new house. A house can be duplicated multiple times, and the duplicated number does not have to be associated with the number/effect combination. Cross off the top-most, lowest-numbered space in the "bis" column.

At the end of the game, subtract the smallest, unchecked number from the final score.