This rule approximates natural player behaviour, formalising the edge
case.]
-Greens
-------
+Greens etc.
+-----------
-When a green chip talks about "the last or second-last chip in your
-post", apply the rule for each of the last *three* chips, not just the
-last *two*.
+When a chip (typically green, but also eg some blacks) talks about "the
+last or second-last chip in your post", apply the rule for each of the
+last *three* chips, not just the last *two*.
[Rationale: Greens seem not to come up. In my experience, even with
this change they are still quite weak.]