//@version=3
study(shorttitle="BB+%", title="Bollinger Bands plus Percent Indicator", overlay=true)
length = input(20, minval=1)
src = input(close, title="Source")
mult = input(2.0, minval=0.001, maxval=50)
basis = sma(src, length)
dev = mult * stdev(src, length)
upper = basis + dev
lower = basis - dev
plot(basis, color=#cc0000)
p1 = plot(upper, color=#33cccc)
p2 = plot(lower, color=#33cccc)
fill(p1, p2, color=#00ffff, transp=97)

high_symbol = barstate.islast ? open + (open * 0.1) : na
low_symbol = barstate.islast ? open - (open * 0.1) : na
plotshape (high_symbol, style=shape.diamond, color=#00ffff, location=location.absolute, show_last = 1)
plotshape (low_symbol, style=shape.diamond, color=#00ffff, location=location.absolute, show_last = 1)