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

Distractor grid 1:

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

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 unique pattern where all rows except the last one contain exactly three 'x' elements with at least one 'x' in the second column, distinguishing it from both distractor grids.
assistant
Expression: Grid with two horizontal rows of three 'X' and two vertical columns of three 'X'
assistant