Row to column and column to row using awk

Question

I have two files containing as below

cat file1.txt
a b c 
1 2 3

cat file2.txt
a
b
c
1
2
3

I want file1 to be arranged as

a         


        

Answer 1

I'd use xargs for this:

$ xargs -n1 < file1
a
b
c
1
2
3

$ xargs -n3 < file2
a b c
1 2 3