The wise soul who put slide rule art together did have a point...probably before solar powered calculators were invented. Then again, an electromagentic pulse could knock a calculator out, so I will keep this handy and above my desk, for now.
If I was born before calculators existed, I would have stabbed myself with a slide rule. Even an abacus seems more user friendly. Seriously, this thing takes mad skill to use, and those that had to use it, I salute you!