defparam cumulateorders = false

ONCE uptrend = 1
ONCE downtrend = 1

n = 1

Boxsize = 20

turnafternn = 4
LowerBorderBox = round((close / Boxsize) - 0.5) * Boxsize
ONCE DowntrendLow = LowerBorderBox
ONCE UptrendHigh = LowerBorderBox

If LowerBorderBox > LowerBorderBox[1] then

If uptrend = 1 then
downtrend= 0
ONCE DowntrendLow = LowerBorderBox
  If LowerBorderBox > UptrendHigh then
   UptrendHigh = LowerBorderBox
  endif
endif

If downtrend = 1 and LowerBorderBox >= DowntrendLow + (turnafternn * Boxsize) then
  UptrendHigh = LowerBorderBox
  uptrend = 1
  downtrend = 0
endif

elsif LowerBorderBox < LowerBorderBox[1] then

  If downtrend = 1 then
  uptrend = 0
  ONCE UptrendHigh = LowerBorderBox
   If LowerBorderBox < DowntrendLow then
    DowntrendLow = LowerBorderBox
   endif
  endif

  If uptrend = 1 and LowerBorderBox <= UptrendHigh - (turnafternn * Boxsize) then
   DowntrendLow = LowerBorderBox
   uptrend = 0
   downtrend = 1
  endif

endif

If uptrend = 1 and uptrend[1] = 0 then
buy n contracts at market
endif

If downtrend = 1 and downtrend[1] = 0 then
sellshort n contracts at market
endif

set stop ploss 350