Accumulation
Elements are progressively added without removing previous ones. Count increases monotonically.
Understanding this pattern
In accumulation patterns, each frame adds one or more new elements while keeping all existing ones. A grid might fill one cell per step, or pie slices expand by a fixed angle each frame. The prediction requires knowing where the next element appears — which often follows a secondary path or counting rule.
Example Question
Pattern Rule
The sequence follows a diagonal path across a 3×3 grid, with two elements (X and O) moving symmetrically toward the center, overlapping, then continuing to opposite corners. Frame 1: X at top-left corner, O at top-right corner. Frame 2: X moves one step right and down to middle-left, O moves one step left and down to middle-right. Frame 3: Both elements converge at the center cell — complete overlap. Frame 4: X moves one step right and down to middle-right, O moves one step left and down to middle-left (positions swap relative to frame 2). Frame 5: X reaches bottom-right corner, O reaches bottom-left corner. Frame 6: Both elements should converge back at the center cell — overlap again.
Explanation
Option D shows one black cell at the exact center of the grid — both X and O at the center cell, matching step 6. Option A shows X at top-left and O at top-right, which corresponds to frame 1 — not the next step after frame 5. Option B shows X at bottom-right and O at bottom-left, a repeat of frame 5 — no progression occurred. Option C shows X at top-left and O at bottom-right, which breaks the symmetric diagonal movement pattern. Option E shows X at center and O at bottom-left, stopping one step short — O did not complete its movement to center.
How to spot it
- The number of elements grows from frame to frame
- Nothing disappears between frames — only additions
- A region fills progressively (grid cells, pie slices, dots)
Common traps
- Assuming linear growth when the pattern adds 1, then 2, then 3
- Missing the path rule that determines WHERE new elements appear
- Confusing accumulation with replacement (elements change, not add)
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