Drawing a simple figure from verbal
instructions
This unit was inspired by a task titled “T-shirt Design”, which appearing in Balanced Assessment Middle Grades Assessment Package 1, pp. 105-121.
Students work in pairs. Each person needs a blank sheet of paper, pencil, ruler, compass, and protractor (depending on the complexity of the figures to be drawn).
Goal of the lesson.
Suppose person A draws a design on a sheet of graph paper. Person A hides his/her design from person B, and A must tell B, verbally, how to draw A’s design. B must follow the instructions A gives, and B tries to draw exactly the same design that A has drawn. When B is finished, the two designs are compared. Discrepancies are noted, and A and B discuss how to improve the instructions.
Part 1. Drawing graph paper.
A. Using a sheet of typing paper (8 1/2 by 11 inches), each person should draw a one-inch grid of squares.
B. Discuss the difference between a square on the grid (there are 8*11 = 88 one-inch squares on the grid) and a corner of a square, a point. On the grid below a square is colored in:
On the grid below, the corners (vertices) of the squares are marked with dots. There are 9*12 = 108 corners.
Part 2. Person A draws a design on his/her graph paper. The drawing is limited to circles, half circles, quarter circles, and straight lines (drawn with a ruler). At most five lines can be drawn. Here is an example:
Part 3. Person A now must hide his/her drawing from Person B, and describe the drawing so that Person B can draw it. Person B should draw as person A explains.
Here is a possible description.
In this example, we will always draw from one corner to another corner.
a. Starting at the lower left corner of the rectangular graph paper, go to the right four inches and up five inches, and make a dot.
b. Set your compass at a radius of four inches, and using the dot as a center, draw a circle.
c. Using a ruler, draw a horizontal diameter through the circle, from the left edge to the right edge (of course it goes through the center).
d. Start at the center of the circle. Go up three inches and to the left one inch, and make a dot (on the corner of a square).
e. Using a ruler, make a straight line between that dot and the center of the circle.
f. Now make another straight line with a ruler that joins the same dot with the left end of the circle’s diameter.
g. Start again at the center of the circle. This time, go down three inches and over one inch, and place a dot.
h. Using a ruler, make a straight line between that dot and the center of the circle. Notice that your new line extends a previous straight line that you drew.
i. Now make another straight line with a ruler that joins this same dot with the right end of the circle’s diameter.
That’s all!