Do this a couple of times, you can work it out.

----4----------------------3-------3----------------
-------3----------------------1-------1-------------
----------2-----------------------------------------
----------------------------------------------------
----------------------------------------------------
----------------------------------------------------

Then maybe do this:

----------------------------------------------------
----------------------------------------------------
---5---5---5---5------4---4---4---4-----------------
---5---5---5---5------4---4---4---4-----------------
---3---4---3---4------2---3---2---3-----------------
----------------------------------------------------

Then something like this:

----------------------------------------------------
----------------------------------------------------
----------------------------------------------------
---4---5---7-----4--5--7-----4---5---7-----4--5-5-5-
---2---3---5-----4--3--5-----2---3---5-----4--2-3-2-
---2---3---5-----2--3--5-----2---3---5-----2--2-3-2-