A Certain Equivalence (Week 3)

One of the more intriguing things I have learned this week was the equivalence statement,
(not P or Q) <=> (P => Q).
When Professor Heap first showed it on the screen and said that we should convince ourselves it is true, I was startled for a moment as I wondered how that could even be true. As it came to, I actually decided to take the time to quickly sketch a truth table of  (not P or Q). The "not" threw me off at first, so then I decided to write down the possibilities of P, then the negated possibilities right next to it in the same column. After also filling in the Q column, I compared the negated P and Q, which yielded true for three rows, and false for one. And that one row that produced a false statement had true for the original value of the antecedent P (false after P's negation) and false for the consequence Q, exactly the same result as the standard implication (P => Q). Thus that had slightly convinced me to believe it is the truth.