Update pattern-system.md

Added Iba's paper as a reference on building pattern languages; and also proposed another plane for classifying InnerSource patterns.

Author: NewMexicoKid

pattern-system.md

@@ -74,6 +74,9 @@ patterns. I also think that the criterions for a useful pattern system
 postulated by Frank Buschmanns are sensible and might serve as a role model for
 our InnerSource pattern system.
 
+### A pattern language for creating pattern languages (Takashi Iba)
+Takashi Iba has published an article in the ACM Digital Library from PLoP 2016:  [A pattern language for creating pattern languages: 364 patterns for pattern mining, writing, and symbolizing](https://dl.acm.org/citation.cfm?id=3158175&CFID=831673585&CFTOKEN=74341142&qualifier=LU1011674) - for those without ACM DL access, there is [an earlier draft of the paper from PLoP 2016](http://www.hillside.net/plop/2016/papers/three/26.3.pdf).
+
 ## Candiate Classifications
 
 This section shall serve to collect individual proposals for systems of ISC 
@@ -97,7 +100,20 @@ patterns into:
 - organizational and
 - social.
 
+### Tim Yao
+
+Another plane that would be useful is the plane of type of InnerSource. InnerSource programs can be structured to accomplish different goals: e.g.,
+
+* Product Development
+* Tools Development
+* Innovation (Proof of concepts, demos)
+* Shared components development
+
+Each of these programs have some unique characteristics. E.g., sometimes in Product Development, the open source characteristic of voluntariness has to be sacrificed to ensure that sufficient development resources are dedicated to meet customer commitments and schedules. Similarly, there might be a need to limit code visibility/transparency for certain very proprietary products while making use of InnerSource methods to facilitate joint development between different business lines.
+
+#### Pattern Classification vs. Pattern Language
 
+One lesson from PLoP 2017 was that the GoF book presented not a pattern language but a (useful) collection of patterns. Ideally, while we may have different classification systems for our InnerSource patterns, I think we want to develop a Pattern Language--a group of patterns that work together to solve a larger problem (e.g., "How do I build a new InnerSource program appropriate for my company") vs. a collection of patterns that might not have a larger goal.