TR   0  1  2  3  4  5  6  7  8  9  
        [x  x  x  x][y  y  y  y  y  y]

0.   _/  A  B  C  D  E  F  G  H  I  J
        *P1         *P2                 set pointers, bgn=0
1.   A/  A  B  C  D  E  F  G  H  I  J   *P1 -> TR
2.   A/  E  B  C  D  E  F  G  H  I  J   *P2 -> *P1

                    *P1         *P2     shift pointers
3.   A/  E  B  C  D  I  F  G  H  I  J   *P2 -> *P1

              *P2               *P1     shift pointers
4.   A/  E  B  C  D  I  F  G  H  C  J   *P2 -> *P1

              *P1         *P2           shift pointers
5.   A/  E  B  G  D  I  F  G  H  C  J   *P2 -> *P1

        *P2               *P1           shift pointers
(now P2 points to "bgn" location (0), so fetch from TR:)

6.   A/  E  B  G  D  I  F  A  H  C  J   TR -> *P1
           *P2               *P1        increment pointers, bgn=7
7.   H/  E  B  G  D  I  F  A  H  C  J   *P1 -> TR
8.   H/  E  B  G  D  I  F  A  B  C  J   *P2 -> *P1

           *P1         *P2              shift pointers
9.   H/  E  F  G  D  I  F  A  B  C  J   *P2 -> *P1

                       *P1         *P2  shift pointers
10.  H/  E  F  G  D  I  J  A  B  C  J   *P2 -> *P1

                 *P2               *P1  shift pointers
11,  H/  E  F  G  D  I  J  A  B  C  D  *P2 -> *P1

                 *P1         *P2
(now P2 points to "bgn" location (7), so fetch from TR:)

12.  H/  E  F  G  H  I  J  A  B  C  D   TR -> *P1 (last iteration)

        [y  y  y  y  y  y][x  x  x  x]