Introscopia

int Z, W;
String[] titles = { "frame", "mousePressed()", "mouseDragged()", "mouseReleased()", "mouseClicked()", "mouseWheel()", "keyPressed()", "keyReleased()", "keyTyped()" };
float x, h, M;
float[] y;

void setup(){
  size(1200, 300);
  
  x = 0;
  for( int i = 0; i < titles.length; ++i ) if( textWidth( titles[i] ) > x ) x = textWidth( titles[i] );

Introscopia

ArrayList<Particle> PS; //Here's our array of objects
IntList marked;
float G = 0.2, one_over_pi = 1/PI;

float cx, cy;
float torus_x, torus_y, torus_l, torus_b, torus_w, torus_h;  // position and dimensions of the torus box.

byte background_mode = 0;
boolean record = false; //true; //

Introscopia

  void gravitate( Particle p ){                                                                     
    PVector grav = new PVector(1,0);                                                                
    grav.setMag( G*(p.area()) / sq( constrain(dist(pos.x, pos.y, p.pos.x, p.pos.y), 1, 100000) ) );                           
    grav.rotate(atan2(p.pos.y - pos.y, p.pos.x - pos.x ));                                          
    acc.add(grav);
  }

Introscopia

This creates a toroidal topology,
hence the name of the method and variables I used to accomplish this.
A torus is a doughnut shape, we say that these top-bottom and right-left
"warps" form a toroidal topology because 
the only way to take a piece of paper and fold it such that 
it actually connects those edges in that way 
is to make a doughnut shape with it.

Introscopia

 //rudimentary inelastic collisions
  for(int i = 1; i < PS.length; ++i){   // loop through the particle array
    for(int j = 0; j < i; j++){           // only checking each pair of objects once.
      if( PS[i].alive && PS[j].alive ){
        if( PS[i].pos.dist( PS[j].pos ) < PS[i].R + PS[j].R ){
          int a = ( PS[i].R > PS[j].R )? i : j;      // the larger one
          int b = ( a == i )? j : i;                 // absorbs the smaller one.
          PS[a].vel.set( PS[b].vel.mult( (PI*sq(PS[b].R)) / (PI*sq(PS[a].R)) ) );  // gains it's kinetic energy
          PS[a].R = sqrt( sq(PS[a].R) + sq(PS[b].R) );  // and it's area.
          PS[a].D = PS[a].R * 2;                        // refresh the diameter.

Introscopia

Particle[] PS; //Here's our array of objects

float G = 0.2;

void setup(){
  size(800, 600);
  
  // initialization for the array...
  PS = new Particle[60];
  // and for each object.

Introscopia

// Object of Arrays
Particle_system the_system;

Class Particle_system{
	PVector[] positions, velocities;
}


// Array of Objects
Particle[] particle_system;

Introscopia

PVector pos, vel;
float R, D;

void setup(){
  size(400, 400);
 
  pos = new PVector( 200, 200 );
  vel = new PVector( random(-3, 3), random(-3, 3) );
  R = 10;
  D = 2 * R;

Introscopia

/*
bouncing ball demo in 20 line of (actual) code.

first up we're declaring all our variables.
( We're telling the computer how much memory we're gonna use and we're making up names for the each memory chunk )
they're all float(floating point numbers), which means they can be decimals, as well as whole numbers.
*/
float ball_X, ball_Y, ball_VX, ball_VY, ball_R, ball_D;

// Setup is the function which runs once when the program starts up, it's where we...