Suppose you traveled back in time—say 40,000 years into the past—and then you got stuck. What would you do? How would you rebuild all the stuff that you like? That's the premise of the book How to ...

We’ve been loving the variety of entries to the 2025 One-Hertz Challenge. Many a clock has been entered, to be sure, but also some projects that step well outside simple timekeeping. Case in point, ...