David Mortman

Ninety years ago KitchenAid released their first countertop mixer, which weighed in at about 69 pounds. More interestingly, the mixer also had a special socket that allowed users to attach assorted add-ons for new functionality such as slicers, shredders and meat grinders. Today this sort of extensibility of countertop-appliances is old hat for KitchenAid and their competitors.  The interesting thing about this socket is that it has not changed in size or shape since the very first version was released. As a result, you can buy a brand new attachment, say the pasta rollers and it will work in every single version of every KitchenAid stand mixer ever made. Talk about backward compatibility!