§@·~5

1. Construct the envelope of the light rays emitted from a radiant point source at infinity after reflection by the semi-circle.
2.Construct the envelope of the light rays emitted from a radiant point source at the circumference after reflection by the same circle.
3.Construct the envelope formed by a fix diameter of a circle rolling along a straight line.
4. Construct the envelope formed by a fix diameter of a circle rolling along a fixed circle of the same size.
5.Construct the envelope formed by a fix diameter of a circle rolling along a fixed circle twice the diameter.
6.Construct this figure:
7.Construct this figure:
8.Construct this design:
9.Construct the nested squares as thus:
10.Constructed nested triangles as thus:
11.Construct this pattern:
12.Construct the family of ellipses         x=(1-t)cos(s), y=tsin(s), s=[0,2Pi]        as t ranges in [0,1].
13.Construct the concentric and coaxial ellipses of constant area:
14.Construct this pattern.
15.Construct this pattern.
16.Construct the reflections of a light ray trapped inside a reflective ellipse. There are two cases.