public static void SimpleSubcircuit()
{
var builder = new CircuitBuilder();
var batteryDefinition = builder
.AddVoltageSource(1, 2, 9)
.AddResistor(2, 3, 1.5)
.BuildSubcircuit(new[] { 1, 3 });
builder.Clear();
builder
.AddDevice(new[] { 0, 1 }, new Subcircuit(batteryDefinition))
.AddSubcircuit(new[] { 0, 1 }, batteryDefinition);
}