-------------------|
-------------------|
-------------------|
1-2-1-1-2-1----1-2-|
1-2-1-1-2-1----1-2-|
1-2-1-1-2-1----1-2-|
------------------------------------------------------------------------|
------------------------------------------------------------------------|
------------------------------------------------------------------------|
--------------------------1-2-1-2---------------------------------------|
0-------------0-----------1-2-1-2---0-------------0-----------7-8-7-8---|
0--0--0--0----0--0--0--0--1-2-1-2---0--0--0--0----0--0--0--0------------|
. . . . . . . . . . . .
I thinks this is how it goes but its worth a try.