int frames = 0;
float newx[];
float newy[];
int newi = 0;
int newn;

float oldx[];
float oldy[];
int oldi;
int oldn;

void setup() { 
size ( 320, 320 );
smooth();

newn = 40;
newi = 0;
newx = new float [newn];
newy = new float [newn];

oldn = 400; 
oldi = 0;
oldx = new float [oldn];
oldy = new float [oldn];

framerate (30);
}


void loop() { 

frames++;

background ( 25 );

stroke ( 200 );
int i;

newx[newi] = mouseX;
newy[newi] = mouseY;

//for ( i = 0; i < newn - 1 ; i++ ) { 
//  stroke ( 200 - i  * 3 );
//  line ( newx[(newi + i)%newn ], newy[(newi + i)%newn], newx[(newi + i + 1) % newn], newy[(newi + i + 1) % newn] );
//}

for ( i = 1; i < oldn - 1 && i < (frames - newn) ; i++ ) { 
  if ( i > oldn - 40 ) { 
   stroke ( 80 - 2 * ( i - ( oldn - 40 )  ) );  
  }
  else { stroke ( 80 ); } 
  line ( oldx[(oldi + i)%oldn ], oldy[(oldi + i)%oldn], oldx[(oldi + i + 1) % oldn], oldy[(oldi + i + 1) % oldn] );
}


beginShape ( LINE_STRIP );
for ( i = 0; i < newn && i < frames ; i++ ) { 
  stroke ( 240 - i  * 4 );
  curveVertex ( newx[ ( newi + i ) % newn ], newy[ ( newi + i ) % newn ] ); 
}
endShape();



for ( i = 0; i < newn - 4 && i < frames ; i++ ) { 

  int pre = ( newi + i ) % newn;
  int cur = ( newi + i + 2 ) % newn;
  int nex = ( newi + i + 4 ) % newn;

  float shift = 0.15 - 0.40 * ( float ) i / (float ) newn ;
  float dx = newx[ cur ] - 0.5 * ( newx[pre] + newx[nex] );
  newx[cur] += dx * shift ;
  
  float dy = newy[ cur ] - 0.5 * ( newy[pre] + newy[nex] );
  newy[cur] += dy * shift ; 
}

newi = ( newi + newn - 1 ) % newn;
oldx[oldi] = newx[newi];
oldy[oldi] = newy[newi];
oldi = ( oldi + oldn - 1 ) % oldn;

}