For example, software reminding you to stretch every once in a while.
I found RemindMe in the windows store but it doesn't have a periodic setting.
>>59345884
cron
>>59345884
Google Keep.
http://www.boost.org/doc/libs/1_53_0/libs/timer/doc/index.html
https://msdn.microsoft.com/en-us/library/system.timers.timer(v=vs.110).aspx