Total Crisis Panic Button
Start Running -- Danger is Imminent
Don't Think -- Stay Fearful and Alert
Here's a clearer photo, taken by Steve Diet Goedde at the corner of Sunset and Silver Lake Blvd a few months ago.
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. His new book is Maker Dad: Lunch Box Guitars, Antigravity Jars, and 22 Other Incredibly Cool Father-Daughter DIY Projects