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 ▢ ▢

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 target grid has a single filled cell in the center of the top row, a filled cell in the center of the second row, and a filled cell in the top left corner of the bottom row. It also has two filled cells in the middle column, with one in the top half and the other in the bottom half. The grid has a filled "X" shape in the center, with arms extending to the top left, bottom left, and middle of the grid.
assistant
Expression: The grid with a horizontal line of five "X"s in the middle row, and two "X"s on either side of it in the rows above and below.
assistant