Answer: What Comes Next? #267

The answer is A: an arrow pointing up.

The finished pattern: an arrow pointing down and right, an arrow pointing left, an arrow pointing up and right, an arrow pointing down, an arrow pointing up and left, an arrow pointing right, an arrow pointing down and left, an arrow pointing up.
The finished pattern.

The rule

The arrow turns 135 degrees clockwise (the way a clock’s hands move) every time. It takes 8 steps to get back where it started, because 8 × 135 = 1080, which is 3 full turns.

The pattern as Python code

Here is a tiny Python program that follows the same rule. Type it into IDLE and run it to print the whole pattern, including the answer.

direction = 135
for step in range(8):
    print("Step", step + 1, "points", direction, "degrees")
    direction = (direction + 135) % 360

When you run it, Python prints:

Step 1 points 135 degrees
Step 2 points 270 degrees
Step 3 points 45 degrees
Step 4 points 180 degrees
Step 5 points 315 degrees
Step 6 points 90 degrees
Step 7 points 225 degrees
Step 8 points 0 degrees

Pixel says: Try changing a number in the code and run it again. Can you make the pattern go on for 20 steps? Meow!