GATE CS 2026 Set 2 Q2 — General Aptitude

To determine which shape from Panel II is the complementary part that forms the black square $PQRS$ when combined with the part in Panel I, we analyze the boundary of the cut:

1. Complementary Fit: The correct piece must have protrusions (outer steps) that perfectly match the indentations (inner steps) of the piece in Panel I, and vice versa.
2. Orientation and Rotation: The pieces in Panel II may be rotated. We need to find the shape that, upon suitable rotation, perfectly aligns with the cut boundary of Panel I to reconstruct a complete, solid square.
3. Matching the Features:
   • By examining the stepped boundary of the piece in Panel I, we can trace its profile.
   • Comparing this profile with the options in Panel II, shape (iii) is the exact complementary shape. When rotated appropriately, its boundary perfectly interlocks with the boundary of Panel I to form the square $PQRS$.

Thus, shape (iii) is the correct complementary part, which corresponds to Option C.