mujoco

<mujoco>
  <visual>
    <global elevation="0"/>
  </visual>

  <default>
    <position ctrlrange="-.2 .2"/>
    <joint axis="1 0 0" type="slide"/>
  </default>

  <option integrator="implicitfast"/>

  <worldbody>
    <light pos="0 0 2"/>

    <body pos="0 0 .15">
      <joint name="0"/>
      <geom size=".05"/>
    </body>

    <body>
      <joint name="1"/>
      <geom mass="1" size=".05"/>
    </body>

    <body pos="0 0 -.15">
      <joint name="2"/>
      <geom mass="1" size=".05"/>
    </body>

    <body pos="0 0 -.3">
      <joint name="3"/>
      <geom mass="1" size=".05"/>
    </body>
  </worldbody>

  <actuator>
    <position name="r=1/3"          joint="0" dampratio=".333" kp="10"/>
    <position name="r=1"            joint="1" dampratio="1"    kp="10"/>
    <position name="r=3"            joint="2" dampratio="3"    kp="10"/>
    <!-- transmission increased by 10: reduce kp by 10^2 -->
    <position name="r=1, g=10"      joint="3" dampratio="1"    kp=".1" gear="10" ctrlrange="-2 2"/>
  </actuator>
</mujoco>