HIPs region of KIC 11717120 (top), where the HIP pattern is dominated by the sine wave (red line), owing to the interference between direct and refracted waves; and the region of KIC 7940546 (bottom), where the two HIP patterns can be determined. The blue and green lines in the bottom panel correspond to the two fitted sine waves with frequencies Δν₁ and Δν₂, respectively. We shifted the green and blue lines by 0.05 for clarity. The red line is the actual fit.