逻辑门中的circle rule

Circle rule is a rule used in digital logic design to determine the output state of a logic gate when its input signals are changing simultaneously. The rule states that if there is an odd number of circles (representing inverters) in the path from the input to the output of a gate, the output will be the logical complement of the input. If there is an even number of circles in the path, the output will be the same as the input. This rule is useful in simplifying logic circuits and reducing the number of gates required to implement a particular function.