| ------------------------------------2-3-4 ----------------------------2-4-3
---------------------2-3-4--------------- -------------------2-4-3-------------
-------------2-3-4----------------------- -----------2-4-3---------------------
-1 2 3 4---1--------1-------------1------- 1 2 4 3---1-------1-------1-----------
up and down, all finger combination ex: 1 3 2 4, 1 3 4 2, 1 4 2 3, 1 4 3 2, 2 1 3 4, 2 1 4 3 , 3 1 2 4 , 3 1 4 2 , 4 1 2 3 etc.
Then do 2 finger same string and cross 2 finger
----------------------------------3-4- ---------------------------------4-3
--------------------------3-4--------- --------------------------4-3------
------------------3-4----------------- ------------------4-3--------------
---1 2 3 4 ----1 2---- 1-2-----1-2---- ---1-2-4-3---1-2---- 1-2----1-2---
etc....
Then do 3 finger same string and cross 1 finger
------------------------------------4- -------------------------------------3
----------------------------4--------- ----------------------------3--------
--------------------4----------------- --------------------3----------------
---1 2 3 4 ----1 2-3-- 1-2-3---1-2-3-- ---1-2-4-3---1-2-4--- 1-2-4---1-2-4--
etc |