题面摘自 Henry E. Dudeney 公版文本；英文为古腾堡原文整理，中文为本站自译，提示、解答骨架和闲谈保留本站原创结构。
The Chinese are a curious people, and have strange inverted ways of doing things. It is said that they use a saw with an upward pressure instead of a downward one, that they plane a deal board by pulling the tool toward them instead of pushing it, and that in building a house they first construct the roof and, having raised that into position, proceed to work downwards. In money the currency of the country consists of taels of fluctuating value. The tael became thinner and thinner until 2,000 of them piled together made less than three inches in height. The common cash consists of brass coins of varying thicknesses, with a round, square, or triangular hole in the centre, as in our illustration. These are strung on wires like buttons. Supposing that eleven coins with round holes are worth fifteen ching-changs, that eleven with square holes are worth sixteen ching-changs, and that eleven with triangular holes are worth seventeen ching-changs, how can a Chinaman give me change for half a crown, using no coins other than the three mentioned? A ching-chang is worth exactly twopence and four-fifteenths of a ching-chang.
中国人是一个充满好奇心的民族，做事方式也很奇怪。据说，他们使用的锯子具有向上的压力，而不是向下的压力，他们通过向自己拉动而不是推动工具来刨削木板，在建造房屋时，他们首先建造屋顶，然后将其升起到位，然后继续向下工作。在货币方面，该国的货币由价值波动的两两组成。两千两堆起来，高度不足三寸。常见的现金由不同厚度的黄铜硬币组成，中间有圆形、方形或三角形的孔，如图所示。它们像纽扣一样串在电线上。假设十一枚圆孔的钱值十五钱，十一枚方孔的钱值十六钱，十一枚三角孔的钱值十七钱，那么一个中国人怎么能给我半个克朗的零钱，除了上面提到的三枚硬币之外呢？一张清张正好值两便士和一张清张的十五分之四。
提示 1
先把每一步允许做什么写成状态表。
提示 2
找一个不会随操作改变的量，或把对象分成互斥类别。
提示 3
检查构造是否覆盖全部对象，而不是只给出一个漂亮例子。
完整解答
固定主人面向门口，就消除了旋转重复。先数其余人任意排列，再减去两位指定朝圣者相邻的情形。相邻时把这两人看成一个双人块，块内部有 2 种顺序；最后用总数减去坏排列。
Dudeney 的趣题常把难点藏在“看起来可以试”的地方。别急着猜答案；先把图、表或状态画出来，再问哪些限制一直没有变。这也是它和 Carroll 逻辑题互补的地方：一个拆句子，一个拆结构。