1 s=".sdrawkcab si gnirts sihT"

 2 puts s.reverse #This string is backwards.

 3 puts s #.sdrawkcab si gnirts sihT

 4 s.reverse!  

 5 puts s #This string is backwards.

 6 

 7 puts "Three little words".split(/\s+/)

 8 #Three

 9 #little

10 #words

11 

12 puts "Three little words".split(/(\s+)/)

13 #Three

14 #

15 #little

16 #

17 #words

Because the regular expression

/(\s+)/ includes a set of parentheses, the separator strings themselves are included in the returned list.