If you create a number box and then open the "properties" window there is a section that says "messages", "receive symbol", "send symbol"

Could someone explain what this means?

I'm brand new to pd.

I'd like to make a template that represents the midi channel by color. So I'd like to change the channel number to one between 0-999, say

[channel]
|

• |
  [mod 1000]
  |
  [drawpolygon $1 .....]

The problem is, how do I call the channel field of the struct from inside the template? I know I can call channel directly inside [drawpolygon ....], but then I can't do any arithmetic on it before using it as a color.

I know I could define a new field in the struct, say clr, set up an abstraction to define it correctly from channel, then call clr inside [drawpolygon ....], but that seems ugly.

OK, so it seems that the ugly way is the only way. That's rather disappointing.

OK, thanks!

So the symbol you choose is supposed to be a new one, to identify this particular "channel" of communication? I had been thinking it might be the name of the quantity you want to send/receive.