An aldis lamp and heliograph simulator.
After seeing a documentary about WW2 and convoys, I was impressed of the skills of the Aldis lamp operators.
Since I know Morse code I tried to read the code, this was harder than I thought.
I searched Internet for any software based Aldis lamp / Heliograph simulators, but could not find any.
So I decided to make one on my own. Here it is, absolutely free (gratis). It's called Superaldis.
You can use to program to improve your skills or even more fun,
use the computer screen as an Heliograph or an aldis lamp to communicate with another user.
(Remember to adjust the screen contrast and brightness for higher light emission).
Older CRT screens work best, they are faster and brighter.
If you are using a LCD screen, the newer the beater (faster update frequency).