In [ ]:
ellipse(50, 50, 25, 25);
In [ ]:
void draw() {
    ellipse(50, 50, 25, 25);
}
In [ ]:
void draw() {
    background(128);
    ellipse(mouseX, mouseY, 25, 25);
}
In [ ]:
size(500, 500);
// stem
fill(0, 255, 0);
rect(300, 250, 10, 500);
// flower
fill(255, 255, 0);
triangle(300, 250, 400, 200, 450, 220);
fill(255, 250, 0);
triangle(300, 250, 420, 270, 350, 300);
fill(255, 245, 0);
triangle(300, 250, 260, 270, 250, 220);
fill(255, 240, 0);
triangle(300, 250, 220, 180, 290, 180);
In [4]:
%%javascript

alert("Hello!")
In [3]:
size?

See http://processingjs.org/reference/ more more information.