There are 2 shapes on a 8x8 grid. Which shape is closest to the brown right_triangle in terms of Manhattan distance? The final answer is the grid position of the closest shape like (row_index, column_index).
<think>Target shape: brown right_triangle at (1, 0)
Distance from target shape to gray right_triangle at (4, 3): 6
Closest shape is the gray right_triangle at (4, 3) with distance 6</think>

<answer>(4, 3)</answer>