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

Distractor grid 1:

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

Distractor grid 2:

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 where the bottom row is all filled, and each row above it has one more filled cell than the one below it. 

assistant
Expression: The target grid has more X-shaped cells than either of the distractor grids, particularly in the upper left and lower right corners where there are four consecutive X-shaped cells. Additionally, it has fewer empty cells compared to the distractor grids. In particular, the target grid has only one empty cell in the upper left corner, while both distractor grids have two empty cells each in their respective upper left corners. The target grid also has a higher density of
assistant