Backquoted lists allow evaluation of items that are preceded by commas.
For example:
>`(2 ,(+ 3 4)) (2 7)Any number of commas may appear inside a backquoted list, and at any depth inside that context. For example:
> `(4 ,(+ 1 2) '(3 ,(+ 1 2)) 5) (4 3 '(3 3) 5)
© Colin Allen & Maneesh Dhagat