very short, but, its good
[ Tab from: https://www.guitartabs.cc/tabs/m/misc/blues_riff_tab_ver_2.html ]
E|------------------------------------------------------------------------|
B|---------------------------------------------------------------------5~-|
G|-------------------4~--------------------------------------5-3h5h3------|
D|---------5-3h5h3------------------5-3h5h3--------------------------5----|
A|-----------------5------------------------5----------3--3---------------|
E|---3--3---------------------3--3------------3---------------------------|
repeat several times