You also control the density of the snowstorm at the promt at the start of the program. I find a value of about 800 works well, but you can experiment.
The simulation works by dropping a pixel, then, when it lands on something,
checks to see if it can move right or left. If it can, it does so. This is a reasonably good way of simulating a snowstorm.
I'm sure this program could be improved, and indeed if you find a way of improving it - well done!
The pointer was designed by me using a very good program from an ancient copy of Acorn User, so thanks to whoever wrote it! Also thanks to THE DATAFILE PD forthe rather smart !Help display (you're looking at it!). Finally, thanks to the following for their help and encouragement: