12 Bar Blues

'half bend
''full bend

This is played in most blues songs

Riff1  3,4,-3',3

Riff2  4,4,-3,4

Riff3  3,-3',4,-4''

This is the order its played in 

Riff1 *4
Riff2 *2
Riff1 *2
Riff3 *1
Riff2 *1
Riff1 *2
Repeat 

The bends don't have to be played but it sounds better with them.