| Clue | Source | Date |
|---|---|---|
| Renal calculus (6-5) | ||
| Renal mass (6-5) | ||
| Working on tiny desk with mathematical base for calculus | The Telegraph Toughie | 14 Jun 2022 |
| Hard deposit in a bladder | New York Times | 12 Jan 2021 |
| Hard thing to pass? | USA Today | 28 Apr 2015 |
| Hard thing to pass? |