Not impressed. Lisp’s LOOP macro did it 40 years ago:

First example:

(loop for (x y) on (cons 0 arr) by #'cddr
         counting (and (= 0 x) (= 1 y)))

Second example:

(loop for (x y z) on '(0 1 2 3 4 5 6 7 8 9 10 11 12) by #'cdddr
         do (format t "~a ~a ~a~%" x y z))

It’s slightly longer, but also more readable, IMO. And not that it matters here, but the Lisp version will probably run ~20-50x faster by default.