Groups the elements of a list distant of a regular interval <ncol> and returns these groups as a list of lists. Ex. (list-modulo '(1 2 3 4 5 6 7 8 9) 2) => ((1 3 5 7 9) (2 4 6 8)) Ex. (list-modulo '(1 2 3 4 5 6 7 8 9) 3) => ((1 4 7) (2 5 8) (3 6 9))