My guess is that it would take you about 10 seconds to write a couple sentences, so there might be some overlap depending on what you'd decided to do. If you chose to do something interesting instead of just sit there, then I think you'd have a hard time completing the description of what you did before you'd start to "step on the toes" of your next 10 second interval. In other words, if you did something during the first 10 seconds that took you longer than 10 seconds to write, then at 20 seconds you'd write, "I wrote about what I did during the first 10 seconds". Now, after 20 seconds would depend on how long it took you to write about what you did during the first 10 seconds, and whether you chose to do something with enough time to write about it.
Are we limited to physical experiences? If not, I could daydream quite a scenario and write that down.