In the card game Set, each card has a number of shapes, with four attributes:
Number: The number of shapes is 1, 2, or 3.
Color: Each shape is red, purple, or green.
Shape: Each shape is oval, diamond, or squiggle.
Shading: Each shape is hollow, shaded, or solid.
There is only one card for each possible combination of attributes.
1. Find the number of sets where all three cards are the same for exactly 0 attributes.
2. Find the number of sets where all three cards are the same for exactly 1 attribute.
3. Find the number of sets where all three cards are the same for exactly 2 attributes.
4. Find the number of sets where all three cards are the same for exactly 3 attributes.
