- 3x3 grid numbers 1-9, rows, columns diagonals have same sum
- 9 balls one heavy, scale 2x
- election problem
- 9 dot problem
- toothpicks - 6, make 3 triangles
- logic problems
- 5 & 3 liter containers - make 4 liters
- 1 fox, 2 chickens need to cross river, only take one at a time
oct 25 2009 ∞
oct 31 2009 +
oct 31 2009 +