Estelle happened to glance up to see a girl wave at the people coming into the gym, the twins included. Erion, sensing that Estelle was staring at something, raised his head up and followed her gaze. The twins gazed at the silver-haired girl for a few moments before both of their right hands rose up at the exactly the same time, waved in sync before they dropped their arms and went back to what they had been focusing on previously. Even though Estelle didn't have one of Erion's earbuds in, she was able to hear the music through his ears and soon found herself nodding in time to the beat with her brother. As Estelle focused on her drawing she began quietly humming the melody while Erion mouthed the words to the lyrics, the siblings in perfect sync with each other, their right foot even tapping along at the same time and rhythm.