mattsherman,
Thanks for your diagram. It is lucid.
Is it equally sufficient if I used the second rule (GR at least once) to build frames?
Since [GR] could not come first, I also came up with three sets of frames.
Can you also point me to some clues to how I can better spot the major rule which yields more inferences, in games like this one, where you cannot deduct all that much? Is it the conditional that mostly yields the major deductions?
Thanks!