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X Implies Y

Part 1 :
It's actually rather neat.  If a White Triangle is frobby, then either the "White" or the "Triangle" makes it Frobby.

That makes "Black Triangle" or the "White Circle" unfrobby, because it has BOTH qualifications.  Now, if the "White" and "Circle" are the qualifications, then the "Black" "Triangle" is unfrobby, because it has none of the qualifications.  Vice versa.

White Triangle = Frobby

Black Triangle = UnFrobby
White Circle = UnFrobby

and that makes the Black Circle = Frobby

For the Part 2, you need to turn over the 5 and the F.

You don't need to turn over the 2, because there is
no rule about what might or might not be on the other side of even numbers.

You need to turn over the 5, because there might be a consonant on the other side.

You need to turn over the F, because there might be an odd number on the other side. 

You don't need to turn over the E, because there's no rule that says an Vowels can only be on the flip side of odd numbers.

Fred Garber
Monday, July 29, 2002

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