$ 0 0 1 1 A B C D $ 0 0 1 1 A B C D a A A b B B c C C d D D $ 0 0 S 0 N 0 N 0 $ 0 0 1 1 A B C D < a A a a - A A > a - t b B t t t > b b - B B u b - u u u < < t > u < < > > t c C t t t > c c - C C u c - u u u < < t > u < < > > t d D t t t > d d - D D u d - u u u < < t > u < < ^ < > > > < > < < ^ S < S < < v S $ v v 0 0 v v 1 S ^ < $
Note that non-ascii characters in the above source code will be escaped (such as \x9f).