Spelling principal and lens
The most important person in the opera helps you to spell principal by reminding you that:
Everyone wants to be the principal singer's PAL.
Principal ends in PAL.
It's also worth pointing out how to spell lens,
The plural of lens is lenses, but one lens is not spelt "lense".
To remember that "lense" is incorrect, try pronouncing the E.
LENS – EE
We don't want to be calling a single lens a lens-ee, although it would be cute.