// Nonlinear 
// by REAS <http://reas.com> 

 
int size = 8; 
int legth = 50; 
 
int aSize;           // Height of the shape 
float aPos;          // Position of shape 
float aSpeed;        // Speed of the shape 
int aDirection = 1;  // Left or Right 
 
float bPos; 
float bSpeed; 
int bDirection = 1; 
 
float cPos; 
float cSpeed; 
int cDirection = 1; 
 
float dPos; 
float dSpeed; 
int dDirection = 1; 
 
 
void setup() 
{ 
  size(200, 200); 
  noStroke(); 
  framerate(60); 
  aPos = bPos = cPos = dPos = width/2; 
} 
 
void draw() 
{ 
  background(102); 
  fill(255); 
 
  aSpeed = squared(aPos/float(width-size)) * 2.0; 
  aPos = aPos + ((aSpeed*2.0+0.5) * aDirection ); 
  if (aPos > width-size || aPos < 0) { aDirection = aDirection * -1; } 
  rect(aPos, 0, size, 50); 
  
  bSpeed = quad(bPos/float(width-size)) * 2.0; 
  bPos = bPos + ((bSpeed*2.0+0.5) * bDirection ); 
  if (bPos > width-size || bPos < 0) { bDirection = bDirection * -1; } 
  rect(bPos, 50, size, 50); 
  
  cSpeed = hump(cPos/float(width-size)) * 2.0; 
  cPos = cPos + ((cSpeed*2.0+0.5) * cDirection ); 
  if (cPos > width-size || cPos < 0) { cDirection = cDirection * -1; } 
  rect(cPos, 100, size, 50); 
  
  dSpeed = quadHump(dPos/float(width-size)) * 2.0; 
  dPos = dPos + ((dSpeed*2.0+0.5) * dDirection ); 
  if (dPos > width-size || dPos < 0) { dDirection = dDirection * -1; } 
  rect(dPos, 150, size, 50); 
  
} 
 
float quad(float sa) { 
  return sa*sa*sa*sa; 
} 
 
float quadHump(float sa) { 
  sa = (sa - 0.5); //scale from -2 to 2 
  sa = sa*sa*sa*sa * 16; 
  return sa; 
} 
 
float hump(float sa) { 
  sa = (sa - 0.5) * 2; //scale from -2 to 2 
  sa = sa*sa; 
  if(sa > 1) { sa = 1; } 
  return 1-sa; 
} 
 
float squared(float sa) { 
  sa = sa*sa; 
  return sa; 
}