intro:
e -------------------------------------------------------------
b -------------------------------------------------------------
g -------------------------------------------------------------
d -------------------------------------2--3-----2/4--0---------
a -------3--2--4--0--------3--2--0--4--------3-----------------
e -0--1--------------0--1--------------------------------------
e -------------0-----------------------------------------------
b -------------2-----------------------------------------------
g -------------2-----------------------------------------------
d -------------0-----------------------------------------------
a -------3--2--0-----------------------------------------------
e -0--1--------------------------------------------------------