There is a standard. You can see it at work in the Amsterdam Catalogue of Csound Instruments (not sure if that's the correct title), or in some of the standard textbooks on computer music. 

Google for "csound instrument flowchart" images, and you will see many examples.

Hope this helps,
Mike

-----Original Message-----
>From: Brent Boylan 
>Sent: Sep 21, 2008 6:29 PM
>To: csound@lists.bath.ac.uk
>Subject: [Csnd]  Using Dia for drawing out instrument diagrams
>
>
>I keep wanting to create diagrams of instruments to help me see how things
>are connected. I've tried Dia in the past and then would give up, not having
>any shapes that worked just right. This time I am starting the process of
>creating the shapes to use. My question is, has someone else already done
>this? If not, my next question is, where do I find out the standard for what
>shapes to use for the different opcodes? Is there a standard? 
>-- 
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