There are 5 shapes on a 8x8 grid. Which shape is closest to the purple 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: purple right_triangle at (7, 3)
Distance from target shape to brown square at (3, 0): 7
Distance from target shape to yellow trapezoid at (7, 2): 1
Distance from target shape to gray rectangle at (5, 2): 3
Distance from target shape to red trapezoid at (6, 3): 1
Closest shape is the yellow trapezoid at (7, 2) with distance 1</think>

<answer>(7, 2)</answer>