∀x . ∃y . C(x)→(H(y)∧L(x,y)) You can pick anyone you want (call them x); then I'll pick someone (call them y) such that if x is in the class then y is happy and x likes y. ∃y  .  ∀x  .  C(x)→(H(y)∧L(x,y)) I can pick someone (call them y) such that no matter who you pick (call them x) if x is in the class then y is happy and x likes y. Everyone (in and out of the class) likes at least one happy person. ∀∃ order: I can do it. (⊤) You pick someone, I pick the happy person they like. ∃∀ order: I can't do it. (⊥) I pick someone, you can pick someone in the class that doesn't like them. The class is empty; no one is in it. ∀∃ order: I can do it. (⊤) The if-then never applies, so this is vacuuously true. ∃∀ order: I can do it. (⊤) The if-then never applies, so this is vacuuously true. There's only one happy person in the world. ∀∃ order: I can do it iff everyone in the class likes that person. (∀x . C(x) → L(x, the happy person)) ∃∀ order: I can do it iff everyone in the class likes that person. (∀x . C(x) → L(x, the happy person))