There are 4 shapes on a 8x8 grid. Which shape is closest to the gray trapezoid in terms of Manhattan distance? The final answer is the grid position of the closest shape like (row_index, column_index).
<think>Target shape: gray trapezoid at (7, 1)
Distance from target shape to brown rectangle at (5, 5): 6
Distance from target shape to yellow right_triangle at (6, 3): 3
Distance from target shape to cyan square at (3, 4): 7
Closest shape is the yellow right_triangle at (6, 3) with distance 3</think>

<answer>(6, 3)</answer>