def flo_field(dim=10, f='*', s='.'):
    res = ''
    for i in range(dim):
        line = [f] * dim
        for j in range(dim):
            line[j] = s if (j + i * dim) % 3 == 0 else f
        res += "".join(line) + "\n"
    return res


def tri_field(dim=10, f='*', s='.'):
    res = ''
    for i in range(dim):
        line = [f] * dim
        for j in range(dim):
            line[j] = s if (i > j) else f
        res += "".join(line) + "\n"
    return res