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 ▢ ▢
▢ 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: The target grid features a central X surrounded by empty cells, with the X located in the middle row and middle column, while the first and last rows have a mix of empty and filled cells. The distractor grids have different patterns, with the first having a diagonal X pattern and the second having a more uniform distribution of Xs and empty cells.
assistant
"The target grid is ▢ ▢ ▢ ▢ X."
assistant