In each of the following questions, select a figure from amongst the four…

Concept: In a 2×2 diagonal-square series like this one, every cell is split by a single corner-to-corner diagonal into a black triangle and a white triangle. The two cells that sit diagonally opposite each other in the 2×2 grid always shade their black triangle the same way relative to the grid's centre — either both point it toward the centre (an "inner" corner) or both point it toward the grid's own outer edge (an "outer" corner).

1. The top-right cell and the bottom-left cell form one diagonal pair. Both shade black toward their own outer corner: the top-right cell's black triangle touches the grid's overall top-right corner, and the bottom-left cell's black triangle touches the grid's overall bottom-left corner.

2. The top-left cell and the missing bottom-right cell form the other diagonal pair. The top-left cell shades black toward its inner corner — the corner facing the centre of the grid, i.e. its own bottom-right corner — rather than its outer corner.

3. By the same diagonal-pair rule, the missing bottom-right cell must also shade black toward its inner corner: the corner of that cell facing the grid's centre, which is its own top-left corner.

4. So the missing figure has a diagonal running from its top-right corner to its bottom-left corner, with black filling its top-left corner and white filling its bottom-right corner.

Cross-check: Checking the four alternatives against this description, exactly one alternative shows a diagonal from the top-right corner to the bottom-left corner with black toward the top-left corner and white toward the bottom-right corner — matching the inner-corner shading that the top-left/bottom-right diagonal pair requires. The other three alternatives instead reproduce the exact figure already shown in one of the three visible grid cells (the top-left, top-right, or bottom-left cell), so they cannot also be the new, missing figure.