up-down.pde

import java.util.Calendar;

int bg=0;
int fg=255;

int y;
int[] ysd = new int[12];
int[] ysu = new int[8];
int d=220;
float t=0.0;
color[] palette = {#2D4059, #EA5455, #F07B3F,#FFD460};

void setup () {
  
  size(540, 540, P2D);
  frameRate(30);
  background(bg);
  strokeCap(SQUARE);
 
  for (int i=0; i<ysd.length; i++) {
    ysd[i] = int(lerp(-d,d,float(i)/ysd.length)); 
  }
  
  for (int i=0; i<ysu.length; i++) {
   ysu[i] = int(lerp(-d,d,float(i)/ysu.length));
  }  
}

void draw () {
  
  // Fade or not?
  background(bg);  
  
  //fill(bg, 127);
  //noStroke();
  //rect(0, 0, width, height);
  
  noFill();
  pushMatrix();
  translate(width/2, height/2);
  
  stroke(100);

  for (int i=0; i<ysu.length; i++) {
    float sw = (map(abs(ysu[i]), 0, d, 12, 6));
    
    stroke(palette[i % palette.length]);
    strokeWeight(sw);
    float x1=0.9*(int(-1*sqrt(sq(d)-sq(ysu[i]))));
    float x2 = x1 * -1;
    line(x1, ysu[i], x2, ysu[i]);

    ysu[i]-=1;
    if (ysu[i]<-d) 
      ysu[i]=d;
  }
  popMatrix();
  
  pushMatrix();
  translate(width/2, height/2);
  stroke(fg);

  for (int i=0; i<ysd.length; i++) {
    float sw = (map(abs(ysd[i]), 0, d, 12, 6));

    strokeWeight(sw);
    stroke(palette[i % palette.length]);
    int x1=int(-1*sqrt(sq(d)-sq(ysd[i])));
    int x2 = x1 * -1;
    line(x1, ysd[i], x2, ysd[i]);

    ysd[i]+=2;
    if (ysd[i]>d) 
      ysd[i]=-d;
  }
  popMatrix();

  t+=0.01;

  //saveFrame("frame-####.png");

}