Blues and the start of variation (Guitar II)

We have been playing through the blues (in the key of G) for a few classes. We are now exploring variations to the basic blues progression and the addition of chords such as the diminished 7th.

Here are 3 variations to a simple G Blues progression:

The final photo is a diagram for the diminished chord. This illustrates the chord with a 6th string root and a 5th string root.