//@version=6
indicator("Workshop 06 Range Probes", overlay=true)
floor = input.float(100.0, "Frozen range floor")
ceiling = input.float(110.0, "Frozen range ceiling")
start = input.time(timestamp("01 Jan 2026 00:00 +0000"),
    "Begin observation")
if ceiling <= floor
    runtime.error("Ceiling must be above floor")
inside = close > floor and close < ceiling
ready = time >= start and barstate.isconfirmed
lowerProbe = ready and low < floor and inside
upperProbe = ready and high > ceiling and inside
plot(time >= start ? floor : na, "Floor",
    color=color.blue, style=plot.style_linebr)
plot(time >= start ? ceiling : na, "Ceiling",
    color=color.gray, style=plot.style_linebr)
plotshape(lowerProbe, "Lower probe", shape.triangleup,
    location.belowbar, color=color.blue, size=size.tiny)
plotshape(upperProbe, "Upper probe", shape.triangledown,
    location.abovebar, color=color.orange, size=size.tiny)