[Ask] About awk

[Morning Star]

Hi guys,
I have some string and numeric data in like this format (one line):
1 2 3 4 5 6 7 8 9 10 11 12
and i want the output like this:
1 2 3
4 5 6
7 8 9
10 11 12

How do I do that in awk?

Thanks in advance.

Greetings,

Marco