I'm looking for a simple recursive PHP solution for the Min-Max
algorithm for a game of Connect 4.

Given are:
    2d array:      &$board[][]
      dimensions: x = 1-7 (horizontal squares, 1 is left, 7 is right)
                  y = 1-6 (vertical squares, 1 is top, 6 is bottom)
      values:     0 = empty
                  1 = yellow (starts)
                  2 = red
    $current_counter: the piece which moves now

The result should be the best slot from 1-7, up to a certain depth of
the search tree.

No display, HTML, input etc. are needed -- the only value I need is as
described above (from 1 to 7).

Thanks!