lligraphy: an Abstract Portrait Inside the Body Heart Calligraphy is a biofeedback installation that abstract portraits of participants with their heartbeat data using a pen plotter. The real-time heart rate is mapped to the basic parameters of the pen’s behaviors, namely speed, position, pressure and pendown time. Due to the natural variability in heart rate, every portrait becomes personal and unique graphic, which reflects the natural biorhythm inside human body. The installation explores the role of the body as a channel through which physiology manifests itself in a form of beauty. Author Keywords Biofeedback, heart rate variability, artistic visualization, pen plotter ACM Classification Keywords H.5.m. Information interfaces and presentation (e.g., HCI): Miscellaneous;