If you have a specific resistor value that you want to use but do not have a resistor which can handle the wattage you're working with, then the resiror matrix is one way to handle that problem. Arrange the resitors in equal parallel and series combonations, such as 2x2 3x3 etc. Make sure all resistors are the same value. What you end up with is a large resistor of the same value as the individual ones, but it can handle a much higher wattage
