Shape Cycling
Shapes progress through a defined sequence: triangle → square → pentagon → circle, then repeat.
Understanding this pattern
Shape cycling substitutes one geometric shape for the next in a predefined sequence. A triangle becomes a square, then a pentagon, then resets to a triangle. The cycle length (3, 4, or 5 shapes) determines the periodicity. Often combined with a movement or colour rule, making the shape change easy to miss.
Example Question
Pattern Rule
Each frame shows a square split by a top-left-to-bottom-right diagonal, with one symbol in the upper-right triangle and one in the lower-left triangle. Both symbols advance one step per frame through the same fixed 5-shape cycle (○ → ● → ★ → ◇ → ■ or its reverse), always starting two positions apart from each other.
Explanation
Option C is correct because it applies the single-step cycle advance to both the upper and lower symbols simultaneously, which is the consistent rule across all five visible frames. Option A is tempting because it advances only the upper symbol correctly while leaving the lower symbol at its frame-5 position, which a candidate might choose if they lose track of one region. Option B reverses this error — the lower symbol is correct but the upper symbol lags one step behind — a natural trap for candidates who focus on one triangle. Option D swaps the upper and lower symbols, exploiting the fact that both symbols belong to the same shape set and could plausibly appear in either position. Option E shows the exact state of frame 5 with no advancement, which attracts candidates who confuse 'identifying the last visible frame' with 'predicting the next one'.
How to spot it
- A shape changes form but stays in roughly the same position
- The number of sides increases (or decreases) systematically
- After N frames, the same shape reappears (cycle detection)
Common traps
- Missing the cycle reset — predicting the next shape instead of the first
- Confusing shape cycle with size change (shapes morph vs grow)
- Not noticing that the cycle combines with a separate position rule
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