Re: [ot][spam][crazy][crazy][spam]

[Undiscussed Horrific Abuse, One Victim of Many]

struct triangle {
  pt a;
  pt b;
  pt c;
}

tree structures seem more useful when there is a lot of data to work with.
they can be used with goals of organisation.

but you could make a small one too.

here is an idea: the points are nodes and the lines are edges.

struct pt {
  int x;
  int y;
  struct pt_list {
    pt *this;
    pt *next;
  } neighbors;
};