| Clue | Source | Date |
|---|---|---|
| It may be a boundary between neighboring countries ... or what each set of circles depicts? | LA Times Daily | 06 Feb 2018 |
| It may be a boundary between neighboring countries ... or what each set of circles depicts? | The Washington Post | 06 Feb 2018 |
| It may be a boundary between neighboring countries ... or what each set of circles depicts? |