Hello!
Newbie here . I am trying to alter the "letter K" example to create a flash like page turn ---any help would be appreciated. Thanks
here is where I am so far/**
* Letter K
* by Peter Cho.
*
* Move the mouse across the screen to fold the "K".
*/

color backgroundColor;
color foregroundColor;
color foregroundColor2;

float px, py;
float pfx, pfy;
float pv2, pvx, pvy;
float pa2, pax, pay;
float pMass, pDrag;

void setup() {
 size(640, 480, P3D);
 noStroke();
 
 backgroundColor = color(134, 144, 154);
 foregroundColor = color(235, 235, 30);
 foregroundColor2 = color(240, 130, 20);
 initParticle(0.6, 0.9,  width/2, height/2);
 
}

void draw() {
 background(backgroundColor);
 
 pushMatrix();

 iterateParticle(0.15*(-px+mouseX), 0.15*(-py+(height-mouseY)));

 translate(width/2, height/2, 0);

 fill(foregroundColor);
 drawK();
 pushMatrix();
 
 translate(0, 0, 1);
 translate(0.75 * (px-width/2), -0.75 * (py-height/2), 0);
 translate(0.75 * (px-width/2), -0.75 * (py-height/2), 0);
 rotateZ(atan2(-(py-height/2), (px-width/2)) + PI/2);
 rotateX(PI);
 rotateZ(-(atan2(-(py-height/2), (px-width/2)) + PI/2));
 
 fill(foregroundColor2);
 drawKa();
 popMatrix();
 translate(0.75 * (px-width/2), -0.75 * (py-height/2), 2);
 rotateZ(atan2(-(py-height/2), (px-width/2)) + PI/2);
 
 fill(backgroundColor);
 beginShape(QUADS);
 vertex(-640, 0);
 vertex( 640, 0);
 vertex( 640, -360);
 vertex(-640, -360);
 endShape();
 popMatrix();

}

void initParticle(float _mass, float _drag, float ox, float oy) {
 px = ox;
 py = oy;
 pv2 = 0.0;
 pvx = 0.0;
 pvy = 0.0;
 pa2 = 0.0;
 pax = 0.0;
 pay = 0.0;
 pMass = _mass;
 pDrag = _drag;
}

void iterateParticle(float fkx, float fky) {
 // iterate for a single force acting on the particle
 pfx = fkx;
 pfy = fky;
 pa2 = pfx*pfx + pfy*pfy;
 if (pa2 < 0.0000001) {
   return;
 }
 pax = pfx/pMass;
 pay = pfy/pMass;
 pvx += pax;
 pvy += pay;
 pv2 = pvx*pvx + pvy*pvy;
 if (pv2 < 0.0000001) {
   return;
 }
 pvx *= (1.0 - pDrag);
 pvy *= (1.0 - pDrag);
 px += pvx;
 py += pvy;
}

void drawK() {
 pushMatrix();
 translate(10, 10);
 PImage a= loadImage("jelly.jpg");
 textureMode(NORMALIZED);
 beginShape(QUADS);
texture (a);
 vertex(0, 0, 0,0);
 vertex(200, 0, 0,1);
 vertex(200, 200, 1,1);
 vertex(0, 200, 0,1);
 endShape();
 //translate(10, 10);
 popMatrix();
}
void drawKa() {
 pushMatrix();
 translate(10, 10);
 PImage a= loadImage("eames.jpg");
 beginShape(QUADS);
 texture(a);
 vertex(0, 0, 0,0);
 vertex(200, 0, 200,0);
 vertex(200, 200, 200,200);
 vertex(0, 200, 0,200);
 endShape();
 //translate(10, 10);
 popMatrix();
}