The oldest stone tools discovered so far are from Ethiopia and date back 2.3 million years; they include sharp-edged stone flakes and hand-held choppers -- not things we normally find in our modern-day tool chest [source: Freeman].
The first hand axe didn't appear until about 1.7 million years ago, and since then we've not only been perfecting our craft, we've been improving upon what's inside our toolbox [source: Reardon]. Tools used by the Romans resemble (some very closely) the tools we use today, and by 1916 we were ready to put a little power behind it all: S. Duncan Black and Alonzo G. Decker -- who had launched a business together in Baltimore six years earlier -- applied for the very first patent for a portable power tool [source: Stanley Black & Decker]. Power tools are handy -- you'd be remiss to leave a general-use power drill out of your toolbox, for example. But the power of a tool doesn't need to be constrained by whether or not it's powered by electricity or powered by your hand -- power also lies in the ability to affect a behavior.
With that in mind, let's talk first about the humble paint brush and its ability to unlock the power of color.