More than 100 pen holding robots are the writers for the Phoenix based personalized note writing company Handwrytten, led by entrepreneur David Wachs (pictured).  Much of the success of the venture — which was No. 148 on the 2020 Inc. 500 list of the fastest-growing privately held companies in the U.S. — has sprung from being able to make robots with the skill to produce penmanship that looks nuanced and realistic. That achievement, according to Wachs, sprung from the money saving suggestion by an ASU mechanical engineering graduate to use 3D printing technology to make robot parts that can be created by the company inhouse. (Access to the Phoenix Business Journal online is available only to subscribers.)