Pattern Completion
Pattern Completion items on the NNAT3 ask you to find the one piece that finishes a larger abstract design. The design is shown with a missing section-often a corner, edge, or center-and the answer choices are candidate pieces. The test is nonverbal: color, shape, line direction, and symmetry carry the information, not words.
Core rules
- Treat the visible design as a system. A correct piece continues every line, color region, and shape boundary across the cut edge.
- Check symmetry first. Many patterns are mirror-symmetric or rotationally symmetric; use the matching side to predict the missing side.
- Trace lines across the gap. A diagonal stripe that meets the gap at a given angle must leave at the same angle and width.
- Match color order, not just color presence. Two pieces can contain the same colors in the wrong sequence.
Worked example
A square tile is divided by diagonal stripes running from lower left to upper right, alternating blue and white. The lower-right corner is missing. Along the top edge of the gap, a blue stripe enters; along the left edge, a white stripe enters. The missing piece must continue the blue stripe from the top edge to the right edge and the white stripe from the left edge to the bottom edge, keeping the same stripe width. An answer that shows the right colors but stripes running from upper left to lower right is a mirror image and fails.
Traps
- Choosing a piece that completes the outer outline but not the internal lines.
- Ignoring the direction of a diagonal or the width of a stripe.
- Accepting a color-swapped piece because it looks close.
- Assuming a piece fits because it is the right shape, without checking edge continuity.