The article discusses how Thomas Snyder, a postdoctoral student in bioengineering at Stanford University Medical Center, defended his titled of individual champion at the World Sudoku Championship in Goa, India. The article explains that Sudoku is a logic-based puzzle solved by filling in a grid, typically nine-by-nine, with single-digit numbers. No number may occur more than once in a column, row, or three-by-three subgrid. It is reported that Snyder solved the Sudoku puzzle in 2 minutes, 26 seconds to win the individual title at the 2008 World