Examples of k-iterated spreading models

It is shown that for every $k\in \mathbb{N}$ and every spreading sequence $\{e_n{\}}_{n\in \mathbb{N}}$ that generates a uniformly convex Banach space $E$, there exists a uniformly convex Banach space $X_{k+1}$ admitting $\{e_n{\}}_{n\in \mathbb{N}}$ as a $k+1$-iterated spreading model, but not as a $k$-iterated one.