The purple-tinted sky remained still for long enough that you may have started to question whether or not it had even changed colours to begin with. Only for a few minutes. Soon, however, the colors start changing again. Another gradual fade from purple to a deep violet to blood red.

Maybe it wasn't a trick of the light after all.

The red stays for longer this time, but the moment does not last for too long. Again, the red fades out. Blood red to deep violet to tints of purple. Off and on it fades.