Question

4. Each cell of a `4x4` square is colored with one of two colors, blue or white. The coloring is called successful if every `2x2` square has exactly `3` cells of the same color (i.e., `3` white and one blue OR `3` blue and one white). How many different successful colorings exist? Two colorings are considered different if there is at least one cell colored differently in the two colorings.