Intro - Bridge :
|    Abm     Abm     Abm     Abm  |    Abm     Abm     Abm     Abm  |
|---------------------------------|---------------------------------|
|-----------4-6-------------------|-6-4-----------------------------|
|-------4-6-----------------------|-----6-4-------------------------|
|-4-6-7---------------------------|---------4-7-4-------------------|

Bridge : 

|    Abm     Abm     Ebm     Ebm  |
|---------------------------------|
|-6-6-6---6-6-6-----------4-4-4---|
|-------6-------------4h6---------|
|---------------------------------|