Answers

1.6 Project: draw a letter

Driving · Robot club · about 20 min

What this lesson is about

Plan a path, drive it, leave a trail.

• Plan first
• Stroke one
• Stroke two, two ways
• Your own letters

Questions 6 marks in all

1. [1 mark]The robot starts facing down the mat, at heading 180. What does forward(60, distance=60) draw?

   1. AA line down the mat
   2. BA line up the mat
   3. CA line to the right
   4. DNothing, because forward means up the mat
   Answer: A. Forward is always the way the robot is facing. Facing down, forward draws the downstroke of the L.

2. [1 mark]The robot is facing down the mat. Which command slides it towards the right of the mat, without turning?

   1. Aleft(60, distance=30)
   2. Bright(60, distance=30)
   3. Cturn_right(30, angle=90)
   4. Dbackward(60, distance=30)
   Answer: A. Left and right are from the robot's point of view. When it faces down the mat, its left is the mat's right.

3. [1 mark]The robot faces down the mat at heading 180 and runs turn_left(30, angle=90). What does heading() say? Give a whole number of degrees.

   Answer: 90 (accept within 1). Turning left is anticlockwise, which takes degrees away: 180 minus 90 is 90, facing the right of the mat.

4. [1 mark]Put these lines in order to draw an L with a strafe, starting at the top left facing down.

   Number the lines 1 to 5 to put them in the right order.

   1. left(60, distance=30)
   2. print("done at", position())
   3. forward(60, distance=60)
   4. connect()
   5. from bugbot import *
   Answer:

   from bugbot import *
   connect()
   forward(60, distance=60)
   left(60, distance=30)
   print("done at", position())

   The long downstroke comes first, then the short stroke. Facing down, left slides the robot to the right of the mat.

5. [1 mark]Which way of drawing the second stroke keeps the corner of the L sharpest?

   1. AStrafing, because the robot does not turn
   2. BTurning, because the robot faces the way it goes
   3. CBoth are exactly the same
   4. DDriving backwards
   Answer: A. A turn adds a little error and a little wobble at the corner. A strafe goes straight from one stroke to the next.

6. [1 mark]Which of these letters need drive with rotation to draw well?

   Tick every answer that is true.

   1. AT
   2. BS
   3. CE
   4. DO
   5. EH
   Answer: B, D. T, E and H are all straight strokes. S and O are curves, and a curve needs forward and rotation together.

The task: draw an L

# the two lines every program starts with: the commands, then the robot
from bugbot import *
connect()

# stroke one, stroke two

from bugbot import *
connect()
forward(60, distance=55)
left(60, distance=45)