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 ▢ ▢

Distractor grid 1:

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

Distractor grid 2:

▢ ▢ 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: A grid with an X in the center, and two X's in the top row and bottom row, with the remaining cells empty.
assistant
Expression: The target grid features a unique pattern of X's and ▢'s, with a diagonal line of X's running from the top-left to the bottom-right corner, and a cluster of X's in the center.

In the target grid, the diagonal line of X's distinguishes it from the distractors, as the first distractor grid has a horizontal line of X's, and the second distractor grid has a
assistant