Henry Petroski's 1992 "The evolution of useful things" gets a pass from Book Reviews for Real People. The authors found the writing style in some of the denser passages the "prose equivalent of fingernails on a chalkboard."
Fasteners of dissimilar appearance were also developed to answer the objection to the paper-piercing points altogether.
The image is from patent 1,523,861, which illlustrates one of many improvements on the "Gem" paper clip still in use today. Modern patents are crazy complicated as the patent attorneys have figured out how to patent all kinds of abstractions, but if the first digit starts with 1 there's bound to be a drawing that would make a nice coloring exercise for your mechanical thinker.
CIP 91-39524; LC T212.P465 1992; 609 -- dc20; ISBN 0-679-41226-3; Librarything 1943752; OCLC 24906856; AADL 609 Pe.
The LibraryThing reviews of this work are really quite useful.
This is a book about failure and how failure drives the design of all things. (Jorge Cardoso)