I'm a mathematician, and my reaction here is somewhat different.
I like this one: Young mathematician goes to first grade and the teacher asks who knows what is 1+2. She stands up and says "I don't know what is it, but I do know that it's the same as 2+1 as addition is commutative in the monoid of natural numbers"
#include <stdio.h>
#define SIX 1+5
#define NINE 8+1
int main() {
printf("%d\n", SIX * NINE);
}Was that the 2-3-4 tree? Can't seem to find it now.
unsigned three = 1;
unsigned five = 5;
unsigned seven = 7;