for this scheme, they are weak its middle, you can use :
--DR-----DC--DC-----DL
-----------------------
------MC--MC--MC-----
------------AMC-------
---------ST--ST-------

or
--DR-----DC--DC-----DL
---------------------------
------MC--MC--MC-----
--------------------------
---------ST-ST-ST------

or

--DR-----DC--DC-----DL
---------------------------
MR------MC--MC------ML
--------------------------
---------ST-ST-ST------

good luck!