- this light is usefull for generating lightning effect
- off_value, on_value ( 0.0 - 1.0 ) 0 = dark 1 = full light
- periode = time interval between two groups of flashes
- delay = time between two flashes
- flashes = count of flashes in group
- flash length = time length of one flash
- periode, delay and flashes have min and max value
  in this range are the values random gererated
