(More of a demo than a real proposal.)

  arc> (sequence->list "foo")
  '(#\f #\o #\o)

  arc> (sequence->list (in-range 10 0 -0.5))
  '(10
    9.5
    9.0
    8.5
    8.0
    7.5
    7.0
    6.5
    6.0
    5.5
    5.0
    4.5
    4.0
    3.5
    3.0
    2.5
    2.0
    1.5
    1.0
    0.5)

  arc> (each n (in-range 10 0 -0.5) (out n (expt n 2)))
  '((10 100)
    (9.5 90.25)
    (9.0 81.0)
    (8.5 72.25)
    (8.0 64.0)
    (7.5 56.25)
    (7.0 49.0)
    (6.5 42.25)
    (6.0 36.0)
    (5.5 30.25)
    (5.0 25.0)
    (4.5 20.25)
    (4.0 16.0)
    (3.5 12.25)
    (3.0 9.0)
    (2.5 6.25)
    (2.0 4.0)
    (1.5 2.25)
    (1.0 1.0)
    (0.5 0.25))

  ; use racket's sort
  arc> (|sort| '(a b "foo" 21) (compare > string))
  '("foo" b a 21)

  arc> (|sort| '(a b "foo" 21) (compare < string))
  '(21 a b "foo")

  arc> (sequence->list (in-producer (thunk (bytes-ref (crypto-random-bytes 1) 0)) (%do [< _ 42])))
  '(56 119)

  arc> (sequence->list (in-producer (thunk (bytes-ref (crypto-random-bytes 1) 0)) (%do [< _ 42])))
  '(192 163 45 163 79 184 218 105 67 67 240 228)

  arc> (sequence->list (in-producer (thunk (bytes-ref (crypto-random-bytes 1) 0)) (%do [< _ 42])))
  '(189)

  arc> (sequence->list (in-producer (thunk (bytes-ref (crypto-random-bytes 1) 0)) (%do [< _ 42])))
  '(141 148 243)

  arc> (define (1+ (n 0)) (+ n 1))

  arc> (1+ 21)
  22

  arc> (1+)
  1

  arc> (1+:1+:1+ 21)
  24