(define-syntax data!
  (syntax-rules ()
    ((data! label data)
     (define label 'data))))
(data! x (3.3 6.6 8.8 0.6 6.7 7.4 2.1 9.8 8.3 5.8))
(data! y (-0.8 0.8 2.1 0.2 1.3 3.3 0.4 2.8 4.9 4.7))