| Clue | Source | Date |
|---|---|---|
| Challenging | Wall Street Journal | 21 Apr 2026 |
| A bit tricky | Universal | 16 Jan 2026 |
| Difficult: 2 wds. | Commuter | 11 Dec 2025 |
| Challenging | Wall Street Journal | 26 Feb 2022 |
| Difficult | ||
| Harder than it looks | Wall Street Journal | 08 Oct 2020 |
| Like many things worth doing | Universal | 10 Mar 2020 |
| Difficult | Eugene Sheffer | 07 Jun 2019 |
| Harder than it looks | ||
| Very challenging | Newsday | 31 Oct 2017 |
| Presenting a challenge | USA Today | 15 Oct 2016 |
| Presenting a challenge | ||
| Difficult | USA Today | 14 Jun 2015 |
| Difficult | ||
| Tough | ||
| Like "bein' green," to Kermit | ||
| Taking some doing | ||
| Like "bein' green," to Kermit | ||
| Tough | ||
| Tough | ||
| Tough | ||
| Tough |