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: In the target grid, there are five rows and five columns, with a unique pattern of filled and empty cells. The top row has four filled cells in the first, second, and fourth positions, and an empty cell in the third position. The second row has three filled cells in the first, third, and fourth positions, and an empty cell in the second position. The third row has three filled cells in the first, second, and fourth positions, and an empty cell in the
assistant
Expression: The grid with a filled top row, a filled left column except for the top cell, and a filled bottom-right 3x3 square.
assistant