Start sexscript, then in menu :
script>
edit. Use
open and find the file.
Now you can edit the script. Use
script>
restart in the first window to test it.
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Breaks length is determined by : wait((40+getRandom(20))); inside the loop (that means 40s to 60s, randomly).
Period between beats (in seconds, with decimals) is determined by : def period = (5+getRandom(6))/10.0;
Number of beats is line : def nb2 = 20+getRandom(100);
If you need any more help, please come back, we'll be happy to help you. Also, you might be interested by
this page of documentation.