Design a circuit that adds four 10-bit unsigned binary values and outputs an unsigned binary 10-bit result. The circuit also has a VALID output that indicates when the 10-bit unsigned binary result is valid. Note that when you add two 10-bit numbers, you will generate an 11-bit result (in some cases). Show the top two levels for this solution, meaning a top-level BBD, and the next lower level, which is RCAs and some gates. There is no need to show the next lower level, which would be the gate-level view of the RCAs. State how the circuit is controlled.