Extra whitespace to put the `cond` clauses in columns can make it even more clear, for "visual" looking at code, rather than only "verbal": (define (member

Extra whitespace to put the `cond` clauses in columns can make it even more clear, for "visual" looking at code, rather than only "verbal": (define (member? item set) (cond ((null? set) #f) ((equal? item (car set)) #t) (else (member? item (cdr set))))) For bonus points, line up the key variable in the clauses, and it's easier to see visually that the `cond` is about that one variable: (define (member? item set) (cond ((null? set) #f) ((equal? (car set) item) #t) (else (member? item (cdr set))))) Which accidentally also lines up with one of the procedure's arguments, though I didn't intend that one, but you could double down on that: (define (member? item set) (cond ((null? set) #f) ((equal? item (car set)) #t) (else (member? item (cdr set))))) This isn't some deep thing; just a little example of how sometimes whitespace, other than just indenting at the beginning of the line, helps to exposure some of the structure visually.