Draw a Crescent
You can draw a crescent as two circles. A large yellow circle that is partitally eclipsed by a smaller blue circle. The parameters are:
r1: radius of the large circle
r2: radius of the small circle
off: the distance between the circles' left edges
In addition we can use variables to denote the width and height of the blue rectangle and the distance of the left edge of the circle from the left of the blue rectangle:
Model answer has 39 lines.