---------------------------------------------------------------------------|
---------------------------------------------------------------------------|
9-----9-----9-----9-----9-----9-----10-----10-----10-----9-----9-----9-----| x7
--7-----7-----------7-----7------------8------8------------7-----7---------|
----0-----0-----0-----0-----0-----0------0------0------0-----0-----0----0--|
---------------------------------------------------------------------------|
The seventh time is like this.
------------------------------------------------------0-|
------------------------------------------------------0-|
9-----9-----9----9-----9-----9----10-----10-----10----9-|
--7-----7----------7-----7-----------8------8---------7-|
----0-----0----0-----0-----0----0------0------0----0--0-|
--------------------------------------------------------|
