Why is there 92 pieces in a 91 piece set of dominos?

The confusion arises from the fact that a standard set of dominoes is often referred to as a "double six" set, which includes 28 unique pieces. However, there are also larger sets, such as the "double nine" set, which contains 55 pieces, or the "double twelve" set, which has 91 pieces. When mentioning 92 pieces in a 91-piece set, it could refer to a specific variant or miscounting, as the total number of unique dominoes in any set is based on the highest double tile included.