Coil pack.. Most gas engines have #cylinders/2 of them. Each one powers two cylinders.. This means you have much greater "Dwell time" and a much hotter spark than in the old days when you had but one coil.
So how can it do two? Well one cylinder is just at the top (end) of the EXHAUST cycle when the other paired cylinder is at the ignition point.. So it's firing two plugs.. one is ready to fire and the other is just trying to fir off in exhaust gas (nothing there to burn one hopes)