Random childhood anecdote, posted as individual toot in order to not derail some random joke post about kids these days not being into non-Euclidean geometry:I have three siblings, spaced two years apart each.

[sophieschmieg@infosec.exchange]

Random childhood anecdote, posted as individual toot in order to not derail some random joke post about kids these days not being into non-Euclidean geometry:

I have three siblings, spaced two years apart each. All four of us went to the same high school. My youngest sister's math teacher wanted to do a cute little segment about triangles always having inner angles sum up to 180 degrees. It was supposed to take the form of a trial. My sister was assigned the role of prosecutor charging a triangle accused of having an inner angle sum different from 180 degrees. Obviously, taking her role very seriously, she consulted the Schmieg dinner table, and a plan was hatched, involving a grapefruit and a marker. The trial came, and just as the defense had produced what they thought was irrefutable proof that their client was innocent, my sister took out the grapefruit, drew a triangle connecting one pole to the equator using three right angles, and said "So how do you explain this?!?" Leading to the teacher/judge having to explain non-Euclidean geometry to a bunch of 10 year olds.

And to make this anecdote even better, in a different class the same day she had a substitute teacher who didn't know my sister, but seeing the triangled up grapefruit, approached her and asked her "Are you a Schmieg?". Our family name has racked up quite some reputation…

[sophieschmieg@infosec.exchange]

Nota Bene: since this story took place in Germany, the math teacher in question was quite well paid and had a university level mathematics education to fall back to, which, from having taught that course myself later, should include a full class on geometry, teaching not just the Euclidean, but the Hilbert axiomatisation. He also taught the math extracurricular, so he was very much up to the challenge 🙂.
The triangle on the stand was still acquitted on account of being planar itself, so the story had a happy ending, and no triangles had to go to geometry jail.

[sophieschmieg@infosec.exchange]

It is just now that I realized that you could make the excellent cross-cultural pun that the triangle was pleading the fifth.

Triangle: I'm pleading the fifth, your honor!
Judge: your right to remain silent?
Triangle: no, your honor, I'm pleading that given a line and a point not on that line there is exactly one line through that point parallel to the given line!