Theorem: View the poset $\mathbb{N} = (\mathbb{N},\leq)$ of natural numbers as a category. There is a sequence of distinct functors $G_n:\mathbb{N}\to \mathbb{N}$ such that $G_0(x)=x+1$ and $G_{n+1}\dashv G_n$ for each $n\in \mathbb{N}$.