How to print each couple of args using xargs from a list

I have this list

111
222
333
444
555

I want to print each line to have 2 coupled args, like this:

111 222
222 333
333 444
444 555
555

Is there a way to do this with xargs? or any single liner command (performance is important)

thanks

>Solution :

awk seems more appropriate than xargs:

$ awk 'NR>1 {print prev, $0} {prev=$0} END {print prev}' file.txt
111 222
222 333
333 444
444 555
555