Suppose to implement a simple one-bit bus in a system that has three devices connected to it. Each device has a 1-bit output register that can output to the bus and a 1-bit input register that can read from the bus. The key with a bus is to ensure that only one device is putting data on the bus at a time.

Design a circuit that allows one device at a time to transmit data on the bus. The input registers for all devices should read from the bus all the time.