LUMEN
| Date | Clue |
|---|---|
| 2025-05-01 | Light unit |
| 2025-02-05 | Measure of brightness |
| 2022-12-06 | Bulb unit |
| 2020-06-14 | Light measurement |
| 2020-05-10 | Unit of brightness |
| 2019-12-27 | Light unit |
| 2019-09-28 | Unit of light |
| 2019-08-05 | Measure of light's brightness |
| 2015-08-09 | Projector unit |
| 2014-04-15 | Unit of light |
| 2014-01-04 | Photometry unit |
| 2013-12-21 | Light unit |
| 2007-03-11 | Measure of light |
| 2005-11-20 | Bulb unit |
| 2000-06-05 | Unit of light |
| 1995-10-28 | Light bulb unit |