title: Create particles animation with three.js
body: <p>I am new to three.js, I have created a simple particle app with three.js, but the flow of particles is moving from centre. I want move particles something like displayed in the attached screenshot (top right corner to bottom left corner).
  working code is at <a href="https://jseditor.io/?key=ee98d51a9b4111eab74e00224d6bfcd5" rel="nofollow noreferrer">https://jseditor.io/?key=ee98d51a9b4111eab74e00224d6bfcd5</a>. 
  any reference will be very helpful. Thank you.</p>
  
  <p><a href="https://i.stack.imgur.com/JBf7N.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/JBf7N.jpg" alt="screenshot"></a></p>