Please read the exercise #12 of this page: <a href='https://books.google.com/books?id=We21AwAAQBAJ&lpg=PP1&dq=programming%20principle%20and%20practice&pg=PA665#v=onepage&q&f=true' target='_blank' rel='nofollow'>https://books.google.com/books?id=We21AwAAQBAJ&lpg=PP1&dq=programming%20principle%20and%20practice&pg=PA665#v=onepage&q&f=true</a><br/><br/>There (in page 666) the author states: <i>If you enter the room with the wumpus, or he enters yours, ...</i><br/></br>The "he" returns to the wumpus but why "yours"?