Act as a product designer with 5+ years of experience in sleep technology. Design a smart pillow that monitors sleep quality using [SENSOR_TYPE], [CONNECTIVITY_OPTION], and [MATERIAL]. The pillow should track metrics like [SLEEP_METRIC_1], [SLEEP_METRIC_2], and [SLEEP_METRIC_3], providing real-time feedback via a companion app. Ensure the design is [COMFORT_FEATURE] for optimal user experience. Include visual mockups of the pillow's [AESTHETIC_STYLE] and highlight its [UNIQUE_FEATURE] that sets it apart from competitors.