Historical clue formulations

• Plumbing fixture found under the sink — 2026-07-21
• Curved plumbing piece — 2025-10-11
• Letter-shaped plumbing piece — 2024-09-16
• Under-the-sink fixture — 2022-03-31
• Letter-shaped part of a sink — 2020-10-15
• Plumbing fitting with a bend — 2020-06-20
• Backflow preventer in a drain — 2017-08-27
• Under-the-sink fitting — 2015-11-20
• Plumbing fitting — 2004-07-01