Hi Nicolas – thanks for responding and confirming my thoughts about not being able to do an array. In the meantime I kludged this together:

// p = 60, (1 hour lookback on 1 min chart)
// n = 1
Upper = Highest[p](High)
Lower = Lowest[p](Low)

if Upper > Upper[n] then
PreviousHigh = Upper[n]
PPH = PreviousHigh[n]
PPPH = PPH[n]
endif

if Lower < Lower[n] then
PreviousLow = Lower[n]
PPL = PreviousLow[n]
PPPL = PPL[n]
endif

RETURN upper AS "upper" , lower AS "lower", PreviousHigh AS "PH", PreviousLow AS "PL", PPH AS "PPH", PPL AS "PPL", PPPH, PPPL

While the previous HH and LL’s get drawn, they eventually get overwritten every 60 bars…or whatever p is set to and so it begins to look like strange Darvas boxes. If it is possible to limit to the past 4 HH & LL’s that would be something 🙂

Many thanks

::copperwave

That would get me different overlaid Donchian channels if I understand your suggestion correctly. That isn’t what I am after. All I want to do is preserve an existing HHLL level to the right while re-writing the new one’s as they occur.

Thanks

::copperwave

Hi – OK, well I guess I’ll have to stick to drawing lines manually then 🙂

Thanks

::copperwave