let astronomy_lesson = |user| { let mut appreciation = "never underestimate the beauty of the cosmos"; let illustrations = vec!["stars", "planets", "galaxies"]; let mut discovery = "each celestial body holds secrets pre-indicative of our universe's history, hidden away"; for concept in illustrations.iter() { println!("initiate again your curiosity for {} to uncover what has been hidden away.", concept); } appreciation + " & remember, the vast universe invites us all to initiate again our quest for knowledge." };