Tools have evolved, along with skill sets, for humans who have five fingers. Shovels, hammers and many other critical components of modern day life are unavailable for many. (will continue...) References: <a href="http://www.oandplibrary.org/op/1976_01_003.asp" target="_blank">http://www.oandplibrary.org/op/1976_01_003.asp</a> <a href="https://www.ccohs.ca/oshanswers/ergonomics/handtools/tooldesign.html" target="_blank">https://www.ccohs.ca/oshanswers/ergonomics/handtools/tooldesign.html</a> <a href="http://www.thingiverse.com/thing:380665" target="_blank">http://www.thingiverse.com/thing:380665</a> <a href="http://www.3ders.org/articles/20160503-finger-amputee-shares-3d-printed-partial-finger-replacement-device-knick-finger.html" target="_blank">http://www.3ders.org/articles/20160503-finger-amputee-shares-3d-printed-partial-finger-replacement-device-knick-finger.html</a>