A sign of the times

One day they weren't there.  The next they were.

The signs.

I was intrigued.  Maybe it's a street art installation, like the amazing work done by my friend's son.

These signs appeared just across the bridge that is next to my home.  Who sent this message to us?

I was reminded of another type of unexplained art.....crop circles.  Could these signs also be the work of aliens?

I must investigate.

To be continued.....