A volatility cone plots, for each lookback, the historical distribution of annualized realized volatility (close-to-close, ×√252 for FX business days). The shaded band spans min→max with the median line; the dashed line is today's realized vol. Near the bottom of the cone, the pair is unusually calm (a range/breakout may be brewing); near the top, it's unusually choppy and may mean-revert. Research context, not financial advice.