I spotted these eggs last week in one of my client's office. I thought they were fake eggs until yesterday one of the staff came into the room where I was working and saw the eggs. She told me that they were most likely, pigeon's eggs.
I put a stapler near the eggs for comparison.
Err.. don't ask me why these eggs were there. No nest, just the eggs... weird. My friend didn't think that they will hatch, so she threw them away.