//@version=6
indicator("Workshop 13 Activity Lens", overlay=false)
length = input.int(20, "Prior volume bars", minval=2)
baseline = ta.sma(volume, length)[1]
validCount = math.sum(not na(volume) ? 1.0 : 0.0,
    length)[1]
usable = (not na(volume) and baseline > 0 and
    validCount == length)
relative = usable ? volume / baseline : na
location = (high > low ?
    (2 * close - high - low) / (high - low) : 0)
plot(relative, "Volume multiple", color=color.gray,
    style=plot.style_columns)
plot(location, "Close location", color=color.blue)
hline(1, "Average volume multiple", color=color.gray)