ibly through rotation or reflection).

Step by step
Step 1: Observe how tile X tessellates in arrangement Y — it uses a combination of translation and possibly rotation to interlock seamlessly.
Step 2: For each option tile, test whether its protruding parts exactly fit into the recesses of adjacent copies.
Step 3: Option A — the tile has complementary convex/concave edges that interlock when translated or rotated. ✓
Step 4: Option B — the irregular curves of the tile do not align to create gap-free tiling. ✗
Step 5: Option C — the shape has asymmetric protrusions that cannot pair with adjacent copies. ✗
Step 6: Option D — the tile's shape allows seamless interlocking when arranged in a grid. ✓
Therefore the answer is A and D.

Why wrong options are wrong
Option B: The tile's outline is non-reciprocal — the bumps on one side do not match the recesses needed on adjacent tiles.
Option C: The organic asymmetric shape cannot fill the plane without leaving gaps.

Remember for exam
A tile tessellates if every protruding feature on one edge is mirrored by an equal recess on the opposite edge (or on an adjacent edge for rotational tiling).

c:["product-design","ergonomics","furniture","logical-deduction"] d:["A","D"] b:{"id":"uceed-2022-A224","slug":"uceed-2022-A224","exam":"UCEED","year":2022,"topic":"Design Awareness","tags":"$c","type":"msq","difficulty":"medium","answer":"$d","title":"Shown below are different forms for a step-stool. Which of the forms will remain stable when a person is standing on the top step?","searchText":"Shown below are different forms for a step-stool. Which of the forms will remain stable when a person is standing on the top step? Design Awareness product-design ergonomics furniture logical-deduction","paper":"uceed-2022","question_number":24,"section":2,"part":"A"} e:["visual-pattern","shape-matching","figure-completion","analogy"] f:["A","D"] 11:["3d-geometry","r

Tile X was used to create a pattern which is seamless (without gaps), when arranged as shown in Y. Which of the tiles from the options will create a seamless pattern?