A patterned hot air balloon rises and drifts over a landscape, its burner flashing occasionally with a puff of hot air. The balloon climbs because burning propane heats the air trapped inside the envelope, making it less dense than the cool air outside, so buoyancy lifts the whole rig upward the same way a bubble rises in water. Sideways drift comes purely from prevailing wind, since a balloon has no engine to steer horizontally, and periodic bursts from the burner top up the heat that slowly leaks out through the fabric.