Michael's Fatboy Tesla Coil Black/Copper Coil Fountain Pen - MediumIn the spirit of all past pen inventors, Michael started designing better gripping pens in the early 1990s due to the calluses on his fingers. His efforts resulted in two U. S. Patents being granted to him named Ergonomic Writing Instruments 5,228,794 and Ergonomic Instruments 5,332,324. By licensing the invention to a Taiwan importer, Michael was able to successfully market his patented spiral barrel as The Worm Pen, to Wal Mart and other mass market