Combination of two colors six times

Quick answer：

The combination of two colors six times refers to the process of selecting two colors from a set of six different colors and pairing them together. In this case, each color is paired with every other color exactly once. This can be represented mathematically as C(6,2), which is the number of ways to choose 2 colors out of 6 without regard to order. The result is 15 unique combinations.