When the apocalypse comes, mains electricity winks out after a few days. Water pressure subsides shortly thereafter. Fires consume city blocks within weeks; if it's summer, they spread unchecked. Within a few months, a billion starve to death or die of once-harmless diseases. Worse is to come. Five years in, the batteries within Tokyo Flash's incomprehensible binary wristwatches will also die. How shall we not be able to tell the time easily, unless we think about it for a while, when the zombies are in charge?
Ladies and gentlemen, I present to you Clayton Boyer's Solaris clock.
Solaris Wooden Clock [Clayton's website via Hacked Gadgets ]