Try:
inputs: Price(Close), FastLength( 3 ), SlowLength( 10 ), SignalLength( 16 ),Displaced(0);
variables: vFast(0), vSlow(0), vDiff(0),vDiff1(0), vSignal(0);
vFast = AverageFC (Price, FastLength);
vSlow = AverageFC (Price, SlowLength);
vDiff = vFast - vSlow;
vDiff1=vFast - vSlow...