Tuber magnatum pound ($2200–$4800 per kg); as of December 2009 they were being sold at $14,203.50 per kilogram. In November 1999, what was then the largest truffle in the world was found near Buje, Croatia. The truffle weighed and was entered in the "Guinness Book of Records". The record price paid for a single white truffle was set in December 2007, when Macau casino owner Stanley Ho paid $330,000 (£165,000) for a specimen weighing . One of the largest truffles found in decades, it was unearthed near Pisa, Italy, and sold at an auction held simultaneously in Macau, Hong Kong, and Florence.
Weighing matrix two examples: This is a "W"("2","2"): This is a "W"("7","4"): Two weighing matrices are considered to be equivalent if one can be obtained from the other by a series of permutations and negations of the rows and columns of the matrix. The classification of weighing matrices is complete for cases where "w" ≤ 5 as well as all cases where "n" ≤ 15 are also completed. However, very little has been done beyond this with exception to classifying circulant weighing matrices. There are many open questions about weighing matrices. The main question about weighing matrices is their existence: for which