I think it's just a tunneling bug that happens when the point that make up the wall get messed up a enough. Almost never happens anymore in the v2[1] that I added. This one also allows you to see these points.

[1] https://francisduvivier.github.io/eternal-struggle-with-spee...

Here we have it, an internet toy demonstrating how this asymmetry occurred. I expect physics papers soon.

https://en.wiktionary.org/wiki/%E9%99%B0#Traditional_Chinese (陰) lists the following definitions:

1. cloudy; overcast; gloomy

2. hidden; secret

3. negative [of electrical charge]

4. the Moon

5. shade; shadow

6. north of a mountain or south of a river

7. back side

8. of the nether world; of ghosts

9. (philosophy) "female" principle; yin in yin-yang

10. in intaglio

11. treacherous; deceitful; cheating

12. (dialectal) to deceive; to trick; to trap

13. (Chinese phonetics, of a syllable) open; not having a consonant coda

14. (Cantonese) bangs; fringe

15. genitalia (of humans)

16. a surname

The one (American) person I know who has 陰 as a surname reports that Chinese people are often shocked at her surname upon meeting her. I think it might be a bit like having the surname Death in English (https://www.ancestry.com/last-name-meaning/death?geo-lang=en...).

That is to say, black kind of does mean "bad" here, in the popular conception anyway. Taoism and Buddhism promote a worldview that sees birth and death, creation and destruction, as neither good nor bad, simply inseparable parts of a larger whole. But most everyday people try to avoid darkness, death, destruction, cloudiness, gloominess, shadows, ghosts, treachery, traps, and so on, most of the time. It's more that Taoism teaches that this attempt is foolish.

Not all the senses are unpopular; plenty of people like human genitalia, the Moon, and intaglio, and the shady side of a river can be nicer when it's hot out.