Translation: \\ $p:$ \quad Press button. \\ $q:$ \quad Open window. \begin{tabbing} If I press the button, the window opens. \quad \= $p \imp q$ \\ The window is open. \> $q$ \\ Therefore, I pressed the button. \> $\vdash p$ \end{tabbing} \emph{sequent:} \quad $p \imp q, q \vdash p$ \\ This sequent is not provable. $\mathcal{M} : p = F, q = T$ \\ $\mathcal{M} \models p \imp q, q$ \\ $\mathcal{M} \nmodels p$