| Notice a rather curious fact: In figure 1, you say that the
| "voltage drop in the chosen direction" is V1-V2. And I
| certainly know exactly what you mean. But consider a student
| who has spent a year trying to become accustomed to the rule
| DeltaX=X_final-X_initial (which is apparently very unnatural
| to them). They might likely interpret "the voltage drop in
| the chosen direction" to be V2-V1.
|
This is why I usually sum the voltage "gains" rather than drops around a
closed loop when I do the loop rule.