Snakes are laid out on a plane with the following requirements:

  • Each snake has 3 parts: head, middle and tail.
  • Each snake is touched by exactly one head, one middle, and one tail.
  • Each snake can only touch another snake at most once.
  • Each part of a snake must touch a different part of another snake (no
    head-head, middle-middle, tail-tail).
  • The snakes can’t overlap or cross as they are on a plane.

What is the minimum number of snakes that you need?