Observe the sequence of figures. Which of the following options logically completes the series? Figure 1: An equilateral triangle (points up) with a small square at the top vertex, black in color. Figure 2: The triangle has been rotated 120° clockwise; the small square has moved to the next vertex in a clockwise direction (right) and is now white in color. Figure 3: The triangle has been rotated 120° clockwise; the small square has moved to the next vertex in a clockwise direction (left) and is now black in color. Figure 4: (Space to be filled). Select the figure that continues the sequence.