\begin{sequencediagram}
    \newthread{actor}{Actor}{}
    \newinst[4]{concordia}{:Concordia}{}
    \newinst[2]{eth}{:Ethereum}{}
    \newinst[1]{orbit}{:OrbitDB}{}

    \begin{call}{actor}{Create topic}{concordia}{Topic creation form}
    \end{call}

    \begin{call}{actor}{Add poll}{concordia}{Poll creation form}
    \end{call}

    \begin{call}{actor}{Submit}{concordia}{New topic-poll page}

        \begin{call}{concordia}{Create topic}{eth}{New topic ID}
        \end{call}

        \begin{call}{concordia}{Add poll to topic}{eth}{}
        \end{call}

        \begin{call}{concordia}{Save topic information}{orbit}{}
        \end{call}

        \begin{call}{concordia}{Save poll information}{orbit}{}
        \end{call}

    \end{call}
\end{sequencediagram}