Hiding Ellipse

void setup() {
    //runs exactly once!
    size(500,500);
    background(#6F3255);

}

void draw() {
        //repeats forever and ever and ever
        //background rectangle
        fill(#895EA8);
        rect(0,0,width,height);

        //some triangles
        fill(#2B2C4D);
        triangle(250,10,230,100,290,50);
        triangle(300,60,280,150,340,100);

        //my sprite
        fill(#ABD0CD);
        stroke(#3AA1A3);
      ellipse(mouseX, mouseY, 20, 20);

        //my rectangles
        fill(#2B2C4D);
      rect(200,200,100,100);
        rect(400,400,100,100);

}