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 has a diagonal line of filled cells starting from the top-left corner, with the first and last rows having two filled cells each, and the middle row having three filled cells.
assistant
Expression: The target grid features a unique pattern where the fourth row and the fifth row each have three consecutive filled cells on the left side and a single filled cell on the rightmost position, separated by an empty cell in the fourth column.
assistant