Visualizing the geometry and sound of a Harley-Davidson v-twin engine: p5.js sketch. Run this animated sketch at the slowest speed and observe that the flywheel mass pushes each cylinder through compression, without direct assistance from the power stroke. Also, the longer exhaust period of 405 degrees is produced by the left (rear) cylinder.
"The only reason for time is so that everything doesn't happen at once." -Albert Einstein