(a)

USING: arrays kernel locals locals.parser locals.types
locals.rewrite.closures math prettyprint sequences quotations ;
IN: checks

<<

[let* | x [ "x" make-local ]
        x' [ "x" make-local ]
        b [ x [ 10 + ] x' prefix 2array 1array ]
        le [ b x 1quotation <let*> dup .  ]
        la [ x' 1array le 1quotation <lambda> dup . ] |
    la rewrite-closures first . ]

>>

(a) output:

[let* | x [ x 10 + ] | x ]
[| x | [let* | x [ x 10 + ] | x ] ]
[
    1 load-locals 0 get-local 10 + load-local
    0 get-local 2 drop-locals
]