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

Distractor grid 1:

X X X X ▢
▢ ▢ ▢ ▢ ▢
X ▢ X ▢ X
▢ ▢ ▢ ▢ X
▢ ▢ ▢ X X

Distractor grid 2:

▢ 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 is the one with three filled cells in the top row, second from the left to fourth from the left. It also has a filled cell in the second row, fourth from the left, and a diagonal line of filled cells from the third row, first from the left, to the fifth row, third from the left.
assistant
Expression: The grid with a column of three X's in the middle and two rows of two X's at the top and bottom.
assistant