size(400, 400);
line(120, 80, 340, 300);

size(400, 400);
line(120, 80, 340, 80);
stroke(126);
line(340, 80, 340, 300);
stroke(255);
line(340, 300, 120, 300);

// Drawing lines in 3D requires P3D
// as a parameter to size()
size(400, 400, P3D);
line(120, 80, 0, 340, 80, 60);
stroke(126);
line(340, 80, 60, 340, 300, 0);
stroke(255);
line(340, 300, 0, 120, 300, -200);