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 grid has a diagonal line of "X" marks from the top left to the bottom right. 

assistant
Expression: The grid has two columns with three filled cells each, and the remaining cells are empty. The top row has two filled cells, and the bottom row has three.
assistant