def _find_start(score_matrix, align_globally):
    """Return a list of starting points (score, (row, col)).

    Indicating every possible place to start the tracebacks.
    """
    nrows, ncols = len(score_matrix), len(score_matrix[0])
    # In this implementation of the global algorithm, the start will always be
    # the bottom right corner of the matrix.
    if align_globally:
        starts = [(score_matrix[-1][-1], (nrows - 1, ncols - 1))]
    else:
        starts = []
        for row in range(nrows):
            for col in range(ncols):
                score = score_matrix[row][col]
                starts.append((score, (row, col)))
    return starts