My original Pickett & Eckel, Inc. slide rule.  Purchased circa 1950.  This slide rule had trig functions.  There were no hand calculators at the time.  My first PC was an Olivetti P602 portable electronic calculator utilizing a wire loop memory.   I spent so much time on it, that my wife thought she had lost me, and called it "Miss Olivetti"!
    It literally took weeks to pound out the first simulations of the gravitational force, which were wrong!  That was about 1974.
    Note the yellow color of the Pickett & Eckel slide rule, designed to ease eyestrain.  This slide rule was one of the first to have an aluminum body, bamboo being the traditional construction material.  True nurds, such as myself, proudly carried it in a leather case on their way to class.

SLIDE RULES AND LAPTOPS