mujoco

<mujoco>
  <asset>
    <hfield name="hfield" nrow="5" ncol="5" size=".8 .8 .8 .3"
            elevation="1 0 1 1 0
                       0 1 1 0 1
                       1 .5 1 0 1
                       0 1 0 0 1
                       0 1 0 0 1"/>
  </asset>

  <include file="ray_swing.xml"/>

  <worldbody>
    <body pos="-.5 .002 0" euler="10 50 -40" mocap="true">
      <geom type="hfield" hfield="hfield"/>
    </body>
  </worldbody>
</mujoco>