You are given three grids, where each of them is 5 by 5 in size.
Grids have empty cells marked with "▢" and filled cells marked with "X".
Your task is to generate a referring expression that best describes the target grid while distinguishing it from the two other distractor grids.
The first grid is the target grid, and the following two grids are the distractors.

Target grid:

X ▢ ▢ ▢ X
X X ▢ ▢ X
X ▢ X ▢ X
X ▢ ▢ X X
X ▢ ▢ ▢ X

Distractor grid 1:

X ▢ ▢ ▢ X
X X ▢ X X
X ▢ X ▢ X
X ▢ ▢ ▢ X
X ▢ ▢ ▢ X

Distractor grid 2:

X ▢ ▢ ▢ X
X ▢ ▢ ▢ X
X X X X X
X ▢ ▢ ▢ X
X ▢ ▢ ▢ X

Instruction: Describe the target grid.
Generate the referring expression starting with the tag "Expression: " for the given target grid. Omit any other text.
Expression: The grid where the second row has two Xs at the beginning and end, the fourth row has Xs in the fourth and fifth positions, and the third column has only one X in the middle.
assistant
Expression: The grid with X's in the corners and a diagonal line of X's from top-left to bottom-right, but not a full diagonal, and two X's in the middle row, one in the second column and one in the fourth column.
assistant