 how the circadian system is organized, and we can use those scientific insights to develop mathematical models. The ones that we've done for jet lag are based on coupled oscillator models. So the idea is that you have a clock in your brain, and there are other clocks in your body, in your gut, and in other tissues. And the question is, how can we model how those clocks all talk to one another and respond to different cues as you recover from jet lag?