On a dark gray blackboard, many mathematical formulas are written in chalkOn a dark gray blackboard, many mathematical formulas are written in chalk
A fighter pilot wearing a helmet on the background of a flying planeA fighter pilot wearing a helmet on the background of a flying plane
A helmeted pilot sits in the cockpit of a black planeA helmeted pilot sits in the cockpit of a black plane
A military plane flies into the clouds with a pilot in the cockpitA military plane flies into the clouds with a pilot in the cockpit