Answer: What Comes Next? #122

The answer is C: an arrow pointing up.

The rule

The arrow turns 90 degrees anticlockwise (the opposite way to a clock’s hands) every time. A quarter turn is 90 degrees, so it takes 4 steps to point the same way again.

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 = 270
for step in range(8):
    print("Step", step + 1, "points", direction, "degrees")
    direction = (direction - 90) % 360

When you run it, Python prints:

Step 1 points 270 degrees
Step 2 points 180 degrees
Step 3 points 90 degrees
Step 4 points 0 degrees
Step 5 points 270 degrees
Step 6 points 180 degrees
Step 7 points 90 degrees
Step 8 points 0 degrees