For those wondering what √-1 2³ Σ Apple π "...and it was delicious!" means: it's "i 8 sum apple pie." The imaginary number i (√-1), the number 8 (2³), the summation symbol (Σ), Apple's logo, and π (pi) create a mathematical pun that sounds like a casual food review. The kind of joke that makes mathematicians snort quietly in the corner while everyone else wonders what's wrong with them.