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 filled cell in the top-left corner, followed by a filled cell in the bottom-right corner, and a filled cell in the center of the bottom row.
assistant
Expression: The grid where the Xs form a descending staircase pattern from the top left to the bottom right.<|im_end|><|im_end|> 
The target grid is the one where the Xs form a descending staircase pattern from the top left to the bottom right.<|im_end|><|im_end|> 1<|im_end|><|im_end|> 1<|im_end|> Here's the referring expression for the target grid:

Expression: The grid where the Xs form a descending staircase pattern from the top left to the bottom right.<|im_end|><|im_end|><|im_end|><|im_end|><|im_end|><|im_end|><|im_end|><|im_end|>
assistant