  We show that Ravenel's spectrum $X(2)$ is the versal $E_1$-$S$-algebra of
characteristic $\eta$. This implies that every $E_1$-$S$-algebra $R$ of
characteristic $\eta$ admits an $E_1$-ring map $X(2)\to R$, i.e. an
$\mathbb{A}_\infty$ complex orientation of degree 2. This implies that
$R^\ast(\mathbb{C}P^2)\cong R_\ast[x]/x^3$. Additionally, if $R$ is an
$\mathbb{E}_2$-ring Thom spectrum admitting a map (of homotopy ring spectra)
from $X(2)$, e.g. $X(n)$, its topological Hochschild homology has a simple
description.
