Question: Douglas Engelbart, presenter of the 'Mother of All demos' computer demonstration at the Association of Computing Machinery is best known for facilitating the development of which computer device in a precursor to graphical user interfaces?
{'answer': 'computer mouse', 'supporting_facts': [['The Mother of All Demos', 0], ['Douglas Engelbart', 0], ['Douglas Engelbart', 1], ['Douglas Engelbart', 2]]}