请描述一下三角形的窟窿是什么样子的。
火从三角形的窟窿开始燃烧。[{'character': '火', 'pinyin': 'huo3', 'highest pitch': 9.56, 'lowest pitch': 7.73, 'duration': 0.21, 'prosody hierarchy': 'null'}, {'character': '从', 'pinyin': 'cong2', 'highest pitch': 9.54, 'lowest pitch': 7.73, 'duration': 0.26, 'prosody hierarchy': '#1'}, {'character': '三', 'pinyin': 'san1', 'highest pitch': 11.11, 'lowest pitch': 9.54, 'duration': 0.22, 'prosody hierarchy': 'null'}, {'character': '角', 'pinyin': 'jiao3', 'highest pitch': 11.11, 'lowest pitch': 6.73, 'duration': 0.19, 'prosody hierarchy': 'null'}, {'character': '形', 'pinyin': 'xing2', 'highest pitch': 8.52, 'lowest pitch': 6.91, 'duration': 0.19, 'prosody hierarchy': 'null'}, {'character': '的', 'pinyin': 'de5', 'highest pitch': 9.28, 'lowest pitch': 8.01, 'duration': 0.12, 'prosody hierarchy': '#1'}, {'character': '窟', 'pinyin': 'ku1', 'highest pitch': 10.66, 'lowest pitch': 8.01, 'duration': 0.21, 'prosody hierarchy': 'null'}, {'character': '窿', 'pinyin': 'long5', 'highest pitch': 10.54, 'lowest pitch': 6.62, 'duration': 0.22, 'prosody hierarchy': '#1'}, {'character': '开', 'pinyin': 'kai1', 'highest pitch': 8.85, 'lowest pitch': 7.25, 'duration': 0.19, 'prosody hierarchy': 'null'}, {'character': '始', 'pinyin': 'shiii3', 'highest pitch': 7.92, 'lowest pitch': 6.18, 'duration': 0.15, 'prosody hierarchy': '#1'}, {'character': '燃', 'pinyin': 'ran2', 'highest pitch': 6.18, 'lowest pitch': 5.32, 'duration': 0.2, 'prosody hierarchy': 'null'}, {'character': '烧', 'pinyin': 'shao1', 'highest pitch': 8.88, 'lowest pitch': 6.18, 'duration': 0.32, 'prosody hierarchy': '#4'}]