Drop every N'th element from a list

	;; P16 (**) Drop every N'th element from a list.
	;; Example:
	;; * (drop '(a b c d e f g h i k) 3)
	;; (A B D E G H K)
	(define (drop lst x)
	(let loop ((lst lst) (i 1) (acc '()))
	(let ((revacc (reverse acc)))
	(if (null? lst)
	revacc
	(let ((tail (cdr lst)))
	(cond ((< (length lst) x)
	(append revacc tail))
	((= i x)
	(loop tail 1 acc))
	(else
	(loop tail (+ 1 i) (cons (car lst) acc)))))))))

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