Olga decided to explore the house to find the source of the noise. Tick-tock, tick-tock, she first thought it was a clock, but there were no clock in the house, especially not in the basement, from where the noise seemed to come from. She got down the stairs and remembered the bulb burned out just a few days ago, so she grabbed a torch, the one she used to go to camp with and started to walk towards the noise. One step at a time, following the Tick-tock, Tick-tock that she heard. After just a few step, she spotted a small yellow star, going up and down at the same pace as the noise. No, not a star, more like a mini sun going up, and down, tick, tock. She shifted the beam of her torch so as not to directly illuminate the yellow star. Puzzled, she tried to make sense of what was going on before her eyes. A tennis ball endlessly bouncing right here in her basement. She didn’t even play tennis, nor did anyone she knew. How did this ball get there, and why was it bouncing non-stop, how was it even possible..? She was not really good at physics or anything but she was positively sure that this was not supposed to happen.