Group of Silver Spheres in a Checkborad Pattern over Menlo Park, Ca.

Was a clear day on Memorial Weekend with no clouds or haze. I was preparing for BBQ, looked up and noticed a silver sphere in the sky over Menlo Park, Ca. I figured it was so clear out, I was looking at something very high in the sky like a satellite. After seeing the first one, noticed it was surrounded by other spheres in a checkboard pattern, I pointed them out to my neighbor and his kids; they saw them too. I got my iphone and took a photo. They were far enough away, it's hard to see the one sphere in the photo. When I was aiming to take the photo, we all noticed they were starting to leave so I only caught one; looks like a white spot. There was no noise as they left and they seemed to just disappear, they left so fast. When they were in their pattern, they didn't move. They reflected the sun but not shiny. Were Silver like aluminum but in a matte finish. Could not see details on the spheres..