There are 5 shapes on a 7x7 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 (1, 5)
Distance from target shape to gray square at (1, 3): 2
Distance from target shape to yellow rectangle at (2, 0): 6
Distance from target shape to cyan square at (5, 0): 9
Distance from target shape to brown square at (4, 2): 6
Closest shape is the gray square at (1, 3) with distance 2</think>

<answer>(1, 3)</answer>