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 ▢ ▢
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 target grid has a diagonal pattern of filled cells, with the top-left and bottom-right corners filled and the middle cells empty.
assistant
Expression: The grid has a vertical column of filled cells on the left side, with the first, second, and fifth rows containing filled cells, and the third row having a horizontal line of filled cells in the first three columns, while the fourth row has a filled cell in the fourth column, distinguishing it from the other grids which have different arrangements of filled cells.
assistant