Initial thought was to find a simple 'limit-on-itself' state/var for a very trivial usecase — limit downloads in a stateless JS app. Track n-times, then expire. Reload updates the session. Like radioactive material and its half-life. My brain said: the solution is already there. So CC found it and says; 'old tech, new usecase'. And that it could be a big deal. So here it is, you decide.