Reminds me so much of going through the proof of Schrodinger's Equation at university. We got to a certain point and there was no way to progress to the proof. Then the lecturer showed us that by changing the physical linear measurements into atomic units we could overcome the problem and it would allow us to go through to the final proof.

At that point I decided that the lofty world of metallurgy and materials academia was beyond my ken. And that God really is very clever.