void setup() {
  size(300,300);
}

void loop() {
  background(0,100,150);
  
  noStroke();
  
  // Always specify vertices in clockwise order 
  beginShape(TRIANGLES);
  fill(200,220,255);
  vertex(20,20);
  vertex(20,height-20);
  vertex(width-20,height-20);
  
  fill(255,0,0);
  vertex(20,20);
  fill(255,100,0);
  vertex(width-20,20);
  fill(255,255,0);
  vertex(width-20,height-20);
  endShape();
  
  // curveVertex can take any number of vertices, but is a bit buggy
  // Repeat the start and end points twice.
  fill(255);
  beginShape(POLYGON);
  curveVertex(75,height/2);
  curveVertex(75,height/2);
  curveVertex(75,height/2-75);
  curveVertex(width-75,height/2-75);
  curveVertex(width-75,height/2);
  curveVertex(width-75,height/2);
  endShape(); 

  // bezierVertex must be in groups of 4 vertices
  fill(0,100,255);
  beginShape(POLYGON);
  bezierVertex(75,height/2);
  bezierVertex(75,height/2-75);
  bezierVertex(width-75,height/2-25);
  bezierVertex(width-75,height/2);

  bezierVertex(width-75,height/2);
  bezierVertex(width-75,height/2+25);
  bezierVertex(75,height/2+75);
  bezierVertex(75,height/2);
    
  endShape(); 
}