Hard at work, quarterback Trevor Siemian took snaps Wednesday with the first-team offense, whipping the Broncos into game shape, when a fighter jet flew low over the practice field, rolled majestically and did a gravity-defying climb toward the sun. Entranced by the jet, Paxton Lynch craned his neck with childlike wonder and twisted his back like a pretzel, as the focus of his attention drifted into the wild blue yonder. Want to know why Lynch’s immense physical gifts have failed to translate into a job as Denver’s starting quarterback?