Bottom of the Natatio Pool                             -      -      - 
(-------------------------------------------------)     W <---(M)---> E
                                                        -      -      -

With a swift kick of you feet you plunge to the depths of the pool.  The
water is cool and although a little murky, allows you to see somewhat.  With
you hands you can feel the bottom surface, a small filter grate seems to be
there.  Indeed, there is some evidence that with a little effort it may open
and allow passage.  The pool floor extends west and east.  
A man wades through the waters as he bathes himself.