0.3 Lens tool

Lens manual
Photo: for the application the tool is rotated 90 degrees. The median light beam is drawn. A convex lens has been drawn. The tool is positioned to create the mirror.

Draw a line with the ruler to represent the median light beam.
Align the tool on the line.
Draw the inner contour for the mirror, the convex or the concave lens.
You can add additional light beams to show light breaking and reflection effects.