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 ▢ X X X
▢ X X X X

Distractor grid 1:

▢ X X X ▢
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 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 that has an "X" in all four corners and a single empty cell in its center row.
assistant
Expression: Target grid

The target grid is a 5x5 grid filled with empty cells marked with "▢" and filled cells marked with "X". The grid has four rows and five columns, and each cell contains either a "X" or a "▢". The top-left corner of the grid contains a single "X", and the bottom-right corner contains another "X". The remaining cells contain only "▢". 

To distinguish this target grid from the two distractor grids, we
assistant