title: How to generate "random" points with some minimum distance between them
body: <p>I'm trying to make program which generates "map" with points (cities). Generate only random cities(represented by a graph) isn't problem, but I need set some minimum distance between them (for example, that distance between cities is 5 and more).
  It's about 3 000 cities, so I'm looking for some effective solution.</p>
  
  <p>I can't devise how to solve it, so I will be grateful for any help.</p>