Being able to see your logic helps with education.

Usable on standard MB102 breadboard, only need to connect the power on a single rail, the logic gates carry the power between rails.

Use the logic gates either way around on the same power rails, if the outputs of several logic gates are connected to the same inputs of other gates the lights on the gates that are at zero will not light up with the power of the logic gates that are at one, this will stop confusion over which gate is active and which is not.