light_point
  original name: lightbulb-solid.svg
  https://fontawesome.com/
  free OSI license - https://github.com/FortAwesome/Font-Awesome/blob/master/LICENSE.txt

light_spot
  original name: noun-flashlight-1560557.svg
  https://thenounproject.com/icon/flashlight-1560557/
  by Mohamed Mb

light_directional
  original name: sun-solid.svg
  https://fontawesome.com/
  free OSI license - https://github.com/FortAwesome/Font-Awesome/blob/master/LICENSE.txt

light_environment
  original name: noun-light-3840968.svg
  https://thenounproject.com/icon/light-3840968/
  by Dmitry Vasiliev
