On 2013–02–14 Marco Patzer wrote:

> Now I can use “n” in all MP instances (unless switched off for the
> particular instance). I'd like to define some variables only visible
> in instance “foo”. Something like
> 
>   \startMPinitializations [foo]
>     numeric n; n=4cm;
>   \stopMPinitializations

What I was looking for was (it's even mentioned in the manual):

  \startMPdefinitions{foo}
    …
  \stopMPdefinitions

That means we have:

- MPdefinitions     (for instance-local definitions)
- MPinclusions      (global definitions)
- MPinitializations (global definitions, can be disabled for an MP instance)
- MPextensions      (???, seems to be the same as MPinitializations)

And all four include code for use within MP graphics. That really is
confusing!

> Maybe I'm missing the obvious here.

Yes, I did :)

Marco