/* built with Studio Sketchpad: 
 *   https://sketchpad.cc
 * 
 * observe the evolution of this sketch: 
 *   https://studio.sketchpad.cc/sp/pad/view/ro.yZl3yAwJIpE/rev.1626
 * 
 * authors: 
 *   vinicius philot

 * license (unless otherwise specified): 
 *   creative commons attribution-share alike 3.0 license.
 *   https://creativecommons.org/licenses/by-sa/3.0/ 
 */ 



// Pressing Control-R will render this sketch.

int sizexy = 500;
int i = 0; 
int j = 0;

void setup() {  // this is run once.   
    
    background(255);
    size(500, 500); 
    smooth();
    frameRate(15);
    strokeWeight(0.4);
    colorMode(RGB);

} 

void draw() {  // this is run repeatedly.  

if(i<500){
    
     stroke(1+i, 50, 100, 30);
         
    //grid settings
    line(0,i,500,i);
    line(i,0,i,500);
    
    //fake curve shapes
    
        //outer
    line(0,i,i,500);
    line(i,0,500,i);    
    line(0,i,500-i,0);
    line(i,500,500,500-i);
    
        //inner
        
       line(i,500-i,500-i,0);
       line(0,500-i,500-i,i);
    
        line(500+i,0,0,500-i);
        line(500-i,0,0,500+i);
        
       line(0,i,500-i,500-i);
       line(-i,i,500-i,500-i);
       line(500-i,500-i,i,-i);
       line(500-i,500-i,i,0);
       
       
       line(0,-i,500-i,500-i);
       line(500-i,500-i,-i,0);
        
       
        
        

    i = i+2;
    
    }else{
        i = 1000;
        }
        
if(j<1000){
    
    stroke(200, 200, 200, 255);
    
    line(j,0,0,j);
    
    //line(j,500-j,500-j,0);
    //line(0,500-j,500-j,j);
    //line(500+j,0,0,500-j);
    
    line(500-j,0,500,j);
    
    j=j+20;
    
    }else{
        j = 1000;
        }
}