Sitting on my roof deck writing, the sky was rich blue and clear. I looked up, way up, and saw something slowly passing overhead at commercial airliner altitude moving in an easterly direction. No contrail was visible. It gave off a continuous flashing, solid bright light, something you would never see on a plane during the daytime. It appeared to be rotating. When it flashed, I could make out more of its shape just before its light dimmed. It had no wings. Just when I assumed it’s a wayward satellite possibly spinning out of control, it suddenly turns South. It continued on for a few more seconds before instantly moving in REVERSE direction (North). I only saw it for about 10 seconds more before it was gone.