[NTG-context] How to define an array of pens

[Taco Hoekwater]

> On 22 Jun 2020, at 09:17, Otared Kavian <otared at gmail.com> wrote:
> 
> Hi Hans,
> 
> After learning from you how to define an array of colors and paths, I would like to know how is it possible to define a variable pen size.
> In the following working example below, I would like to replace 
> 
> 	MyPens[j] := pencircle scaled 2pt ;
> 
> by something like
> 
> 	MyPens[j] := pencircle scaled (2+j) pt ;

MyPens[j] := pencircle scaled ((2+j)*pt);

“pt” is just a multiplier variable in MetaPost. there is an
implied multiplication operation, but that only works in
bare-number cases. That is why you need 

 (2+j)*pt

The outer parentheses are to prevent MetaPost from interpreting
your line as 

  (pencircle scaled (2+j)) * pt;

Best wishes,
Taco