Last week I elicited a parametric 3-D design model of a sand battery, a simplified thermal circuit model of it for rough exploration, a backward Euler multiphysics solver to evaluate its performance more accurately, and a volumetric visualization for the resulting temperature distributions, including some custom WebGL shaders: http://canonical.org/~kragen/sw/sandbattery/

It's about 12000 lines of code. I could probably understand every line of it if I spent a couple of months on it, although I'd need to learn some things about WebGL, numerical computation, and solid-state physics. But I elicited it in four days. Probably I'd be better off spending the next couple of months doing something else instead.

So, I was faced with the question of how I could keep the artifact thus created from being completely valueless. My solution was to export the heat-equation solution produced by the solver as (gzipped!) CSV, so that I can use my own code (that I do understand every line of!) to check that the solutions found by the solver are, in fact, solutions.

If that check checks out, the backward Euler solver may be of some value even if I don't understand every line of it.