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   _____    ______    ____     __   __    _____   
  / ___//  /_   _//  |  _ \\   \ \\/ //  /  ___|| 
  \___ \\   -| ||-   | |_| ||   \ ` //  | // __   
  /    //   _| ||_   | .  //     | ||   | \\_\ || 
 /____//   /_____//  |_|\_\\     |_||    \____//  
`-----`    `-----`   `-` --`     `-`'     `---`

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Text this: Head-on collisions of vortex rings upon round cylinders