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 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: Top three rows are filled, bottom two rows are empty except for the first column.
assistant
Expression: The target grid has a clear pattern of filled cells in a square shape, with a mix of light and dark squares. It has a unique arrangement of filled cells compared to the distractor grids, with a consistent pattern of four filled cells in a row and a single empty cell in the middle.
assistant