007+ Outer function increments $v to 1
008+ Inner function reckons $v is 0
007- Outer function increments $v to 2
008- Inner function reckons $v is 1
012+ Outer function catenates 'b' onto $v to give bb
013+ Outer function catenates 'a' onto $v to give bba
014+ Inner function reckons $v is bb
012- Outer function catenates 'b' onto $v to give bab
013- Outer function catenates 'a' onto $v to give baba
014- Inner function reckons $v is bab