<mujoco>
    <body name="walls" pos="0 0 0">
        <body name="innerwall" pos="0 0 0">
            <geom type="box" pos="0 1.5 0" size="0.75 7.5 1"
                  rgba=".12 .4 .9 1"
                  contype="3" conaffinity="3" />
        </body>
        <body name="outerwall" pos="0 0 0">
            <geom type="box" pos="0 10.0 0" size="3.75 1 1"
                  rgba=".12 .4 .9 1"
                  contype="2" conaffinity="3" />
            <geom type="box" pos="0 -10.0 0" size="3.75 1 1"
                  rgba=".12 .4 .9 1"
                  contype="2" conaffinity="3" />
            <geom type="box" pos="4.75 0 0" size="1 11.0 1"
                  rgba=".12 .4 .9 1"
                  contype="2" conaffinity="3" />
            <geom type="box" pos="-4.75 0 0" size="1 11.0 1"
                  rgba=".12 .4 .9 1"
                  contype="2" conaffinity="3" />
        </body>
    </body>
</mujoco>
