This is why (apart from being Irish) I drink a fair bit of tea throughout the day.

Going to the kitchen, boiling water and letting it brew, gets me away from my desk and gives me an opportunity to start thinking out loud while I wait.

Sometimes just getting up out of my chair will shake loose some tough problem and the answer will be clear.

Alas, even after all these years, I occasionally grind away on things rather than remembering this.