Eysenck's PEN Model: 2D Personality Space

Personality psychology's most enduring quantitative model — Hans Eysenck's Psychoticism–Extraversion–Neuroticism (PEN) framework — reduces individual differences to three orthogonal, measurable dimensions. This simulator renders that space two ways at once: a hand-rolled 3D wireframe cube (rotated with rotation matrices and drawn with a perspective divide onto a plain 2D canvas, draggable like a real 3D viewport) and the classic flat E–N circumplex psychometricians actually use in print. A marker moves as you set each trait slider, live readouts report the Euclidean length of your personality vector, and the classic four-temperament classification (Choleric, Sanguine, Melancholic, Phlegmatic) updates instantly from the sign of your Extraversion and Neuroticism scores. Sampling random points and pinning them into a growing population scatter mirrors how psychometric researchers actually visualise cohort data collected from trait inventories like the EPQ-R.