The book is long convexity: it profits from movement in either direction. Each one-minute move banks roughly ½Γ·ΔS², the dots in the field.

That convexity is paid for. The premium decays every minute, so realised movement has to outrun the rent implied by the option's price.

As spot drifts, the book picks up directional delta. When it crosses the band, the position is rebalanced to flat and the accrued move is banked.