A 3D device comprising: a first level comprising first transistors, said first level comprising a first interconnect; a second level comprising second transistors, said second level overlaying said first level; a third level comprising third transistors, said third level overlaying said second level; a plurality of electronic circuit units (ECUs), wherein each of said plurality of ECUs comprises a first circuit, said first circuit comprising a portion of said first transistors, wherein each of said plurality of ECUs comprises a second circuit, said second circuit comprising a portion of said second transistors, wherein each of said plurality of ECUs comprises a third circuit, said third circuit comprising a portion of said third transistors, wherein each of said ECUs comprises a vertical bus, wherein said vertical bus comprises greater than eight pillars and less than three hundred pillars and provides electrical connections between said first circuit and said second circuit.