Need Help with ThinkOrSwim's ThinkScript

[Stock.Jock 10]

I'm attempting to learn and apply the fold command in TOS, but my code is not plotting correctly. Could someone take a look at it and get it to work? I know how to code DO LOOPS in basic language and I'm having trouble doing it in TS. One problem that I have with this is controlling the increments in the iteration. I don't get any syntax errors, but this code does not plot correctly and I cannot figure out why. It should plot horizontal lines at different levels.

 

*****************************************************

def HAV = HighestAll(High);

def LAV = LowestAll(Low);

 

input Direction = {default GridUp, GridDown};

input n = 4;

 

#

# ============================================================

# SWITCH BETWEEN DIRECTIONS

# ============================================================

#

def Mode;

 

switch (Direction)

{

case GridUp:

Mode = 1;

case GridDown:

Mode = 0;

}

 

def StartPoint = if Mode == 1 then LAV else HAV;

 

plot GannLine = fold i = 1 to n

with j = 45

do if Mode == 1 then Sqrt(StartPoint) + ((i * j)/180)

else Sqrt(StartPoint) - ((i * j)/180);

[CrazyCzarina 17]

No idea about this script, for which purpose we use it?