In one of my (middleschool?) science classes, my teacher explained the density equation in terms of a triangle. Of course, we didn't adopt it into our notation.

In one of my (middleschool?) science classes, my teacher explained the density equation in terms of a triangle. Of course, we didn't adopt it into our notation. But I think that just having shown the class the diagram helped a lot of my peers. Later in high school (in a different state), a mathematically-challenged friend was studying logarithms during study hall. Our curriculum used this bizarre, three-step arrow rule to transform logs into the familiar (y = b^e). Having remembered the density triangle, I showed my friend a similar diagram for logs. He said "Thanks. I was probably going to get a zero on the next quiz. I might actually pass now." d = m / v v = m / d m = v * d . /m\ /---\ /v | d\ .-------.