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
▢ ▢ ▢ ▢ ▢
▢ ▢ ▢ ▢ ▢
▢ ▢ ▢ ▢ ▢

Distractor grid 1:

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

Distractor grid 2:

▢ ▢ ▢ ▢ ▢
▢ ▢ ▢ ▢ ▢
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: Top-left X in a sea of empty cells
assistant
Expression: The target grid is characterized by a unique arrangement of filled and empty cells, where four rows and columns intersect to form a distinct pattern. In this grid, there are five rows and five columns, with alternating patterns of empty and filled cells. The top-left and bottom-right corners contain only empty cells, while the remaining cells are filled in. This unique arrangement sets it apart from the other two distractor grids.

The target grid is:
▢
assistant