User contributions
- 21:58, 29 April 2024 (diff | hist) . . (+281) . . 2926: Doppler Effect (→Explanation: Why sirens are ideal analogies. (You might be able to bear the same in a thumping bass, but couldn't entirely rule out that the 'tune' hadn't shited its base(/bass!) key...))
- 07:29, 16 April 2024 (diff | hist) . . (+73) . . 2920: Survey Marker (→Explanation)