Abstract: A building block includes a body. The external surfaces of the body are respectively formed with at least one active side and at least one passive side. The active side is formed with an active positive and an active negative that are magnetic. The passive side is formed with a passive positive and a passive negative. The passive positive is magnetically absorbed and fixed by the active positive; the passive negative is magnetically absorbed and fixed by the active negative. A positive lead wire is between the active positive and the passive positive. A negative lead wire is between the active negative and the passive negative. A load is connected between the positive lead wire and the negative lead wire. When the building blocks are assembled, the passive side is absorbed by the active side. The loads in the blocks are driven and thus the blocks become more diverse.