In which "snake" is not a valid proof technique

Non-proof techniques that students tried today in lab, hesitantly, knowing that I wouldn't buy it:

• proof by picture
• proof by snake
• proof by interpretive dance

This post's theme word is satisfice (v intr), "to satisfy the minimum requirements in a given situation." Your snake is very clever, but it does not satisfice in this class.

Mathematical property of friendship

As part of my lecture, I ask interactive live-polling multiple choice questions. Today, one of those questions was:

Let S be the set of Swarthmore students. Consider the binary relation "is a friend of" defined over S x S. This relation is symmetric.
(a) true
(b) false

The point of this question was twofold: first, I wanted to confirm that everyone was on board with the notation, vocabulary, and definitions involved in reading the question. Second, I wanted everyone to laugh --- the joke is that either answer can be correct, depending on your attitude about friendship. (The class was pretty evenly split across (a) and (b), with one outlier protest vote for (d).)

Imagine my complete and sheer delight when one student's defense of answer (a) was "This is a Quaker school, so we are all friends."

HAH

It is utterly, totally perfect as a response: it confirms that the student understood the concepts AND that they got the joke AND that they joked right back, indicating they're comfortable with the classroom environment already, in week 1.

Dear student: you made my day, 'twas a stellar reply, thank you very much for your in-classroom participation today.


This post's theme word is breviloquence (n), "speak briefly and concisely." English humor favors breviloquence.