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

Distractor grid 1:

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

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 with all rows full of X's except the last row which has only the first and last cell filled with X.
assistant
Expression: The target grid has a unique pattern of filled cells, forming a central square with four smaller squares surrounding it. The filled cells are located at the center and form a square of size 3x3, with an "X" in each corner and a "▢" in the center. This pattern is distinct from the distractor grids, where the filled cells form different shapes and patterns.
assistant