Multiplexer can be used to switch different inpunt-signals to the output.

Check out my last entry on NAND-gates: https://ldjam.com/events/ludum-dare/46/tyson-lee-keep-it-alive-edition/versatility-of-nand-gates

Come tinker and play at: https://ldjam.com/events/ludum-dare/46/tyson-lee-keep-it-alive-edition