\begin{signature}\label{triangle}
    $x$ can be a number.
\end{signature}

\begin{signature}\label{even}
    $x$ can be even.
\end{signature}

\begin{signature}\label{div}
    $x$ can divide $y$.
\end{signature}

\begin{signature}\label{square}
    The square of $x$ is a number.
\end{signature}

\begin{signature}\label{nless}
    $x \nless y$ is a proposition.
\end{signature}