def combinations(c, d):
    """
    Compute all combinations possible between c and d and their derived values.
    """
    c_list = [c - 0.1, c, c + 0.1]
    d_list = [d - 0.1, d, d + 0.1]
    possibilities = []
    for cl in c_list:
        for dl in d_list:
            possibilities.append([cl, dl])
    return possibilities