void setup()
{
background(150,150,150);
size(500,500);  
}

void draw()
{
background(150,150,150);
for (int i = 10; i < 500; i+=10)  
{
int x_1 = 0;
int y_1 = 100 + (int)(random(200));
int x_2 = 0;
int y_2 = 300;

line(x_1+i,y_1,x_2+i,y_2);
  
}
  
}