Happy Tax Day! This week I added a new capability to Optica EM that vastly expands Optica's capabilies for free-form optical design. This new Optica feature is the result of work that I completed more than ten years ago! The original project was to build a flow-cytometer fluorescence detection system. At the time, I needed to make a five-faceted free-form mirror that served as the heart of a optical multiplexer that directed the detected fluorescent light into five different