Stumped...cartesian Product Brain Teaser

I have a table with 2 columns as follows:

COORD LEVEL===== =====1 11 22 23 21 32 33 34 35 3


I need to produce a result that has 1 column that is the concatenation of each COORD separated by a '.' by increasing LEVEL


EX: The result should look like this
1.1.1
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5

Please note that the answer must be flexible enough to handle any number of levels and coordinates (although levels will most likely be less than 5 and coordinates less than 100)

Can this be done in a simple SQL statement?

ANY help is very much appreciated.