. . .more on Formulas 

(HI - LO.1) / (ATR.1(1) * SQRT(1))
(HI - LO.2) / (ATR.1(2) * SQRT(2))
(HI - LO.3) / (ATR.1(3) * SQRT(3))
(HI - LO.4) / (ATR.1(4) * SQRT(4))
(HI - LO.5) / (ATR.1(5) * SQRT(5))
...
(HI - LO.n) / (ATR.1(n) * SQRT(n))

Where n is the RWI Period.

Similarly,

the RWI Low is computed for each bar by calculating the maximum of the following values:

(HI.1 - LO) / (ATR.1(1) * SQRT(1))
(HI.2 - LO) / (ATR.1(2) * SQRT(2))
(HI.3 - LO) / (ATR.1(3) * SQRT(3))
(HI.4 - LO) / (ATR.1(4) * SQRT(4))
(HI.5 - LO) / (ATR.1(5) * SQRT(5))
...
(HI.n - LO) / (ATR.1(n) * SQRT(n))

ATR.1(n) is the n-period Average True Range, one bar back.  HI.n is the high n bars back.
 

. . . more on Charts 

Above is a 5 Minute Bar Chart of an S&P 500 Future Contract (SP`M).  The bold green line in the lower pane represents the High Line of the Random Walk, while the red line represents the Low Line, as specified in the preferences below.

. . . more on Preferences 

• RWI Period - Period used in the calculation of the RWI High and RWI Low as seen above.

• High Line Color - Color, width, and style of the RWI High Line. 

• Low Line Color - Color, width, and style of the RWI Low Line.