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: The grid with three rows of three X's each, surrounded by empty cells.
assistant
Expression: A grid where all rows and columns except the last one contain an unbroken sequence of three 'X's followed by a single empty cell. Each row and column ends with an 'X'. This distinguishes it from the first distractor, which has an empty cell at the start of each row and column, and the second distractor, which has an empty cell in the middle of each row.
assistant