**Puzzle 68**
Define \\((a, b, c) \leq (a', b', c')\\) if and only if \\(a \gt a', b \gt b' \, and \, c \lt c'\\).

**Puzzle 69**
This is a poset since \\(\otimes\\) is + and + is commutative.

**Puzzle 70**
Define \\((a, b, c) \leq (a', b', c')\\) if and only if \\(a \lt a', b \lt b' \, and \, c \gt c'\\). This is also a poset.