Sketch by Leonardo da Vinci (IMAGE) University of Seville Caption Leonardo’s sketch showing the spiral motion of an ascending bubble (from his manuscript known as the Codex Leicester). Credit Universidad de Sevilla Usage Restrictions No restrictions. License Public Domain Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.