Learn and have fun with the geometrical optics. This fantastic app allows you to trace the ray tracing as you would do on a sheet of paper, step by step. A User-friendly and simple graphical interface allows you to use the app without instructions, you can place your components on the optical axis, view the principal and custom rays, determine the various images generated by the lenses. This app is incredibly useful for students but also convenient for the teachers who have to explain the geometrical optics and prepare for exams.