-------------------------------------------------------------------|
-------------------------------------------------------------------|
-------------------------------------------------------------------|
-------------------------------------------------------------------|
-----6-----6---6-----6-----6---6-----6-----6---6-----6-----7-------|
-4-4---4-4---4---0-0---0-0---0---4-4---4-4---4---0-0---5-5---------|      X2
 x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

-------------------------------------------------------------------|
-------------------------------------------------------------------|
-------------------------------------------------------------------|
-------------------------------------------------------------------|  X2
-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-7-7-7-7---|
-4-4-4-4-4-4-4-4-0-0-0-0-0-0-0-0-4-4-4-4-4-4-4-4-0-0-0-0-5-5-5-5---|
 x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

-------------------------------------------------|
-------------------------------------------------|
-------------------------------------------------|
-------------------------------------------------|
-6-6-6-6-6-6-6-6-6-6-6-6-7-7-7-7-7-7-6-6-6-6-6-6-|        X2
-4-4-4-4-4-4-0-0-0-0-0-0-5-5-5-5-5-5-4-4-4-4-4-4-|
   x x x x x   x x x x x   x x x x x   x x x x x

---------------------------------------------------------|
---------------------------------------------------------|
---------------------------------------------------------|
---------------------------------------------------------|
-6--6-6-6--6--6--6-6-6--7--7-7-7--7-6--6-6-6-------------|            X2
-4--4-4-4--4--0--0-0-0--5--5-5-5--5-4--4-4-4-------------|
    x x          x x       x x

now repeat the first part and your done.