The previous posting from half a year ago showed "mixed themes". The basic concept is simple - you take two themes and use some simple blending techniques to create bright and tasty buttons, just like these:

The next version of Substance takes this concept one step further, allowing you to mix more than 2 themes. The results are sometimes better and sometimes worse (4Pill means mix of four base themes):

Here are a few screenshots of bigger buttons to better appreciate the blending in the mixed themes. Larger screenshot of Bottle Green - Lime Green - Bottle Green:

Larger screenshot of Brown - Sunglare - Orange:

Larger screenshot of Barby Pink - Purple - Raspberry:

You can use as many themes as you want, but you'll have to have a pretty powerful CPU for more than 3 themes - i don't have a luxury of hardware acceleration like Java2D team does :)