Explore a gravity simulator in this 28-minute video tutorial focusing on double-planet and trinary star systems. Learn to code physics simulations using VPython, starting with adding a second Earth to our solar system and observing its effects. Progress to creating a rotating third Earth, adjusting orbits, and finally constructing a trinary star system. Discover how to manipulate mass and other parameters to create stable orbital configurations. Access provided code samples to experiment with your own simulations and deepen your understanding of celestial mechanics and computational physics.