<mujoco model="arm">
  <compiler eulerseq="XYZ"/>
  <worldbody>
    <body name="L1">
      <geom type="sphere" size="0.4"/>
      <freejoint name="freejoint"/>
      <body name="L2" pos="1 2 3" euler="5.7295779513082321 11.459155902616466 17.188733853924695">
        <geom type="sphere" size="0.4"/>
        <joint name="J1" type="hinge" axis="1 0 0"/>
      </body>
    </body>
  </worldbody>
</mujoco>
