| Clue | Source | Date |
|---|---|---|
| Poster cardboard | Newsday | 24 May 2024 |
| Postcard paper | Newsday | 27 Apr 2024 |
| Poster project material | Newsday | 20 Aug 2021 |
| Sturdy cardboard | Wall Street Journal | 25 Sep 2019 |
| Cardboard used for posters | Wall Street Journal | 22 Jan 2019 |
| Cardboard used for posters | ||
| Sturdy cardboard | ||
| Poster material | USA Today | 26 Apr 2018 |
| Poster material | ||
| Strong cardboard | Wall Street Journal | 16 May 2017 |
| School poster material | ||
| Poster cardboard | ||
| Sturdy paper | ||
| Poster material, often | ||
| Art supply store stock | ||
| School poster paper | ||
| Poster stock | ||
| Strong cardboard | ||
| School poster paper | ||
| Poster material | ||
| Poster material | ||
| Strong cardboard | ||
| Poster board | ||
| Poster material |