{"subtask_index": 0, "subtask": "Place the block at the correct position to assemble the letter S."}
{"subtask_index": 1, "subtask": "out of view."}
{"subtask_index": 2, "subtask": "End."}
{"subtask_index": 3, "subtask": "Pick up the block on the table."}
{"subtask_index": 4, "subtask": "null."}