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 target grid has a central block of four "X" cells and a peripheral block of one "X" cell on the right side.
assistant
Expression: The target grid has an X in the center cell of the five-by-five grid, with four Xs in a column below it, and three consecutive Xs in the third row from the top, reading from left to right.

Here's the visual representation of the description:

▢ ▢ ▢ ▢ X
▢ ▢ ▢ X X
▢
assistant