tattwa [-hAvtpabdh]
-h Print this help text and exit
-A Set the tattva to Akasha (spirit) [default]
-v Set the tattva to Vayu (water)
-t Set the tattva to Tejas (fire)
-p Set the tattva to Prithvi (earth)
-a Set the tattva to Apas (air)
-b Invert white and black (this will make Akasha white and the background black)
-d Display a dot on the central point of the tattva to focus vision on
Pressing space will hide the tattva, pressing any of the keys relating to a tattva option will select that tattva (e.g. pressing 't' will invoke Tejas)