; overlap (define (overlap xlo xhi ylo yhi) (if (or (< xhi ylo) (< yhi xlo)) '() (list (max xlo ylo) (min xhi yhi)))) (display (overlap 17 25 12 19)) (newline) (display (overlap 12 17 19 25)) (newline) (display (overlap 19 25 12 17)) (newline) (display (overlap 19 25 22 30)) (newline)