Today I learned there is a geometric shape called magatama.

It’s a comma-shaped bead. Popular in Japan’s Jōmon period through the Kofun period, (1000 BC to the 6th century AD).
Kinda cool to think how a particular shape can be considered fashionable so far ago.
Wikipedia suggests the shape may be inspired from a number of sources:
They may be fashioned after animal fangs/teeth
They may be modeled after the shape of fetuses
They may be symbolic of the shape of the soul
They may be modeled after the shape of the moon
That there is meaning and connotation attached to the shape of the magatama itself (i.e. meaning comes from the form itself, and not that magatama has been patterned after anything else)
The Art Institute of Chicago collection has no magatama. Currently, eBay has 819 results for magatama.
Someone in China sells magatama beads for one penny, with free shipping. Well, the auctions start the bidding at one penny. But many of the auctions end up selling for a penny. How? I don’t know how this person makes money. But I put a bid on five magatama beads.

I was inspired to discover the magatama through the substack issue Phthursday Musings: The Season of Green Goblins. In this issue a soccer coach develops a play called the “trapezoid” for his 7-year-old players. I wanted him to yell out some obscure geometric name. Thus, the Wikipedia article “List of two-dimensional geometric shapes” came in handy. MAGTAMA! MAGATAMA!
Google Translate translates the Japanese magatama to “magatama” in English. Nothing too exciting there. Although, the alternative definition is “jewels”. So there ya go. Oh, here’s magatama in Japanese characters: 勾玉
Ends up I was outbid on all five auctions. Winning bids were: $0.11, $0.18, $0.27, $0.70, $1.31
Magatama are clearly stylized cashew nuts that became fashionable because cashew nuts are the tastiest of all nuts…
Cashews are indeed tasty! I’m hard-pressed to come up with a nut tastier than the cashew.