<button n="3">
    <desc>Throttle up</desc>
    <repeatable>true</repeatable>
    <binding>
      <command>nasal</command>
      <script>_ = sprintf("Throttle = %.3f", controls.adjThrottle(0.5))</script>
    </binding>
  </button>

  <button n="2">
    <desc>Throttle down</desc>
    <repeatable>true</repeatable>
    <binding>
      <command>nasal</command>
      <script>_ = sprintf("Throttle = %.3f", controls.adjThrottle(-0.5))</script>
    </binding>
  </button>