pydesign is a very basic GPL2+ package for block designs (http://www.designtheory.org/software/pydesign/). This patch adds a little functionality and a few examples. Needs *lots* more work!
In crea…
```
> sage: time dance(10)
>
>
> ------------------------------------------------------------
> Unhandled SIGSEGV: A segmentation fault occured in SAGE.
> This probably occured because a *compile…