Witnessed strobe/pulsating light while plane watching. i thought it was a silver airplane reflecting, but as the plane changed directions, i noticed the light pattern was too consistent and steady to be a simple reflection of the sun. in the video, the light is flying from right to left through the bottom of the clouds, around 10 sec, it comes out from the bottom right of the break in the cloud. [the part where the cloud thins out before that last puff on the left] in a 11o'clock direction. at 17 secs it flashes right above the highest peak of the cloud on the left, moving left.. it then continues until i lose it behind the tree.