We can do that sort of: When you play tic-tac-toe with your seven-year old nephew or niece, you just look ahead and work backwards.

我们可能会这么做,当你和你七岁大的侄子或侄女,下三子棋的时候,你就会先预测,然后想

耶鲁公开课 - 死亡课程节选

W2 If I go backwards, to work p1 becomes the negative from what I had p2 calculated before, so this becomes minus what I calculated before for w2.

应该是,总功等于,减去,等于。

麻省理工公开课 - 热力学与动力学课程节选