const install = _ => {
    rel(screen, 'touchstart', install)
    rel(screen, 'mousedown',  install)
    adaptiveControlsInstalled = type
    INPUT_MODULES[type].install(
      screen,
      key => keyup  ({ key:lookup(key), preventDefault:_=>_ }),
      key => keydown({ key:lookup(key), preventDefault:_=>_ }),
      options
    )
  }
  // uninstall anything that's already there:
  rel(screen, 'touchstart', install)
  rel(screen, 'mousedown' , install)
  if (adaptiveControlsInstalled) INPUT_MODULES[adaptive