andy07,
The RealCode is relatively straightforward:

'# NewLowPeriod = userinput.integer = 10
If price.Low=price.MinLow(newlowperiod) AndAlso _
    price.Open(1)>price.close(1) AndAlso _
    price.Close>price.Open(1) AndAlso price.Open<price.Close(1) Then pass

I'm not seeing how this would identify engulfing patterns from four days ago. It doesn't preclude them, but it certainly doesn't check for them. Can you give some examples?

Add the Bullish Engulfing condition to your chart.  Then right click on the condition bubble and select Create Market Indicator.  Select the Standard and Poors 500 watchlist and click Next.  Select "Count Passing" then click Next.  Set the number of bars you want to calculate (how far back the market indicator will plot) and set the Recalc frequency.  Then click Finish.