Top: minimum and maximum brightness as a function of time. Data for different Blashko cycles are plotted using different colors. Middle: same as the top but for the phase of both minimum and maximum brightness. Bottom: maximum brightness-maximum phase plot, with sixth order harmonics fits, of CoRoT ID 0105288363 at the first (black), second (blue), third (red), and fourth Blazhko period (green). The arrows indicate the direction of the modulation.