size(400,400);
background(100,100,100);
smooth();

noFill();
stroke(255);
curve(50,50, 200,100, 100,50, 200,300);
rect(50,50, 6,6);
rect(200,100, 6,6);
rect(100,50, 6,6);
rect(200,300, 6,6);

stroke(200,0,0);
bezier(100,300, 300,300, 150,50, 300,100);
rect(100,300, 6,6);
rect(300,300, 6,6);
rect(150,50, 6,6);
rect(300,100, 6,6);

line(100,300, 300,300);
line(300,100, 150,50);