My simple loop is coded

```
for (int i = 0; i < 3; ++i)
{
for (int j = 0; j < 3; ++j)
{
Console.WriteLine("i = {0} j = {1}", i, j);
}
}
```

The output being

i = 0 j = 0

i = 0 j = 1

i = 0 j = 2

i = 1 j = 0

i = 1 j = 1

i = 1 j = 2

i = 2 j = 0

i = 2 j = 1

i = 2 j = 2

How can I change my loop so the combinations for i and j are always unique, even when swapped?

In other words

i = 0 j = 0 -- Unique

i = 0 j = 1 -- Unique

i = 0 j = 2 -- Unique

i = 1 j = 0 -- NOT Unique as 0 1 has occured before

i = 1 j = 1 -- Unique

i = 1 j = 2 -- Unique

i = 2 j = 0 -- NOT Unique as 0 2 has occured before

i = 2 j = 1 -- NOT Unique as 1 2 has occured before

i = 2 j = 2 -- Unique

Has anyone got any idea how this is possible to achieve?