The Biconditional
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
p ≡ q is true when both sides match — both true or both false.
Show
"You advance if and only if you win."
Watch for
The biconditional is two promises: win-then-advance and advance-then-win. Most English "if"s make only one.