Similar Vectors Interdigitated Fuel Cell Electrode 6 2 2 Hydrogen ball Vector material 11 2 5 Pp Cycle 12 1 6 Cno 60 2 34 Nafion Protonic Membrane- Chemical Structure 31 2 17 Unsprayed Graffiti: SUNLIGHT TO HYDROGEN 16 2 8 Beta Decay 26 1 14 Unsprayed Graffiti: HYDROGEN POWERED 9 2 4 Grove Gas Battery 12 2 6