Giant triangular-shaped shadow like UFO in California

On July 13, 2015, a person living in California was outside when he has noticed a giant triangular-shaped shadow flying slowly in the sky. This UFO was almost not visible to naked eye but it was very impressive…

Witness statement:

I was just relaxing in my backyard looking up in the sky saw what looked like a seemingly strange shadow. I noticed it because I was staring at the sky for quite sometime and just watching the clouds slowly move. I literally did not think of anything else but a shadow with extreme accurate shape of a straight line. The object was just and seems to be hovering along with the clouds. The shadow has three straight lines that made it shape like a triangle. After seeing this made me wonder what could caused this and thought to myself maybe a tall building near me was just casting this shadow but then again there was no building that more 250 ft tall in atleast in the 4 mile radius of where I was at and the nearest one is 20 miles away at downtown LA. The object just slowly moved away alongsith the clouds in the horizon.