In this puzzle, a Latin Square is defined as an NxN grid of cells that contain only the digits 1 to N where N is greater than 1, in which digits do not repeat in a row or column. This puzzle contains exactly three Latin Squares: one within another within another. Cells separated by a knight's move (in chess) may not contain the same digit. Digits separated by a white dot are consecutive; digits separated by a black dot are in a 1:2 ratio (ie one digit is double the other).