So I gave the problem below to my Calc 3 class during an “open quiz” (think in-class work), as a means of assessing (a) that they know what the symbols mean without the crutch of loaded letters (like x, y, z) and (b) that they can compute the partial derivatives in the correct manner in the correct order.
It was an unexpected bonus, then, when I got to listen to students say things like “Do we have to take the derivative of donut-e-to-the-chexmix-squared-donut with respect to the chexmix first, or the donut?” and “If you differentiate all horseshoe-sine-horseshoe-flyswatter with respect to the bullseye, you get zero.”