Continuing from the previous lesson, let's look at some more involved explorations of this chord. If you break the chord into sections, you see (from the bottom up) an A7 chord shell with a B major 2,3,5 triad above it. We can see the beginnings of polytonality right there. But let's take it a step further. Look at the second voicing. The 2,3,5 B major triad has been changed to a plain B major triad by dropping the C# down to B:
Thinking about the chord this way, we can see many possibilites. It could be an A7 chord with B major above it. Or a B7+ chord with the 7th in the bottom. Can you think of any others?
Let's pursue the idea of a B7+ chord. What would you play over an augmented 7th? You could play a B wholetone, E harmonic or melodic minor (see last lesson) or perhaps some kind of B Dominant or Mixolydian idea. Bear in mind you're playing this over an A13(#11). That's where the modern polytonal sound can come from.
Let's just try a simple B Dominant Bebop lick over that chord:
This is a great study in polytonality using material you have seen in earlier lessons. Practice on!