void setup() 
{
size(200, 200);
background(#F6FF03);
noStroke();
rectMode(CENTER);
noLoop();
} 

void draw() 
{
draw_rect(150, 50, 100, 100);
draw_rect(150, 150, 100, 100);
draw_rect(50, 150, 100, 100);
draw_rect(150, 150, 100, 100);
draw_rect(50,50,100,100);

}


void draw_rect(int xloc, int yloc, int size, int num) 
{
float grayvalues = 255/num;
float steps = size/num;
for(int i=0; i<num; i++) {
fill(i*#FF0B03);
rect(xloc, yloc, size-i*steps, size-i*steps);
}

}