Lesson 7 · The Challenge of Turning — Knowledge ChecksAnswer key

The robot moves from (2,3) to (3,3). Which direction is that, and what heading number?

1. A.North, heading 0
2. B.South, heading 2✓
3. C.East, heading 1
4. D.West, heading 3

The row went 2 → 3 (row +1). Increasing row means moving down the grid, which is South — heading 2.

Going from (1,5) to (1,4), what does desired_heading return?

1. A.0 (North)
2. B.1 (East)
3. C.2 (South)
4. D.3 (West)✓

The row is unchanged; the column went 5 → 4 (col −1). Decreasing column is West — heading 3.

Starting at heading 0 (N) and wanting heading 3 (W), how many right turns does turn_to make?

1. A.1
2. B.2
3. C.3✓
4. D.0

0 → 1 → 2 → 3: three right turns. Turning right (clockwise) from North all the way around to West is three steps — the loop just keeps going until it matches.

Why must drive_path update self.position after each step?

1. A.To make the robot faster
2. B.So the next desired_heading() compares the next intersection against the correct current position✓
3. C.To reset the heading to North
4. D.It doesn't matter — position is never used again

desired_heading works from the difference between current and next. If position isn't updated, every step after the first computes the wrong direction.