Textures

int x;
int xS = 2;
int y;
int w = 10;
int h = 100;
float rot;
float rotS = PI/20;

float shade = 0; 
float shadeIncrease = -.75;
float shadeR = 255; 
float shadeG = 255; 
float shadeB = 255; 
float randR = random(0, 250); 
float randG = random(0, 250); 
float randB = random(0, 250); 
float nextR = 255; 
float nextG = 255; 
float nextB = 255; 

void setup() {
  size(320, 500);
  background(255);
}

void draw() {
  strokeWeight(3);
  stroke(0);
  fill (shadeR+randR*random(1, 2), shadeG+randG*random(1, 2), shadeB+randB*random(1, 2)); 
  translate(width/2, height/2);
  rectMode(CENTER);
  rotate(rot);
  x+=(xS/2);
  rect(x, y, w, h);
  rot+=rotS;
  if (rot%20>=10) {
    shade = 0;
    shadeIncrease = -.75;
    xS*=-1;
  }
  shade += shadeIncrease; 
  shadeR = shade+shadeIncrease*.2;
  shadeG = shade+shadeIncrease*.2;
  shadeB = shade+shadeIncrease*.2;
}

void mouseClicked() {
  background(255);
  x = 0;
  xS = 2;
  y = 0;
  w = 10;
  h = 100;
  rot= 0;
  rotS = PI/20;
  int colorSchemer = int(random(3));
  if (colorSchemer == 0) {
    //red
    nextR = 250;
    nextG = 0;
    nextB = 0;
  } else if (colorSchemer == 1) {
    //green
    nextR = 0;
    nextG = 255;
    nextB = 0;
  } else if (colorSchemer == 2) {
    //blue
    nextR = 0;
    nextG = 0;
    nextB = 255;
  }
  randR = random(nextR, 250);
  randG = random(nextG, 250);
  randB = random(nextB, 250);
  shadeR = random(0, 250);
  shadeG = random(0, 250);
  shadeB = random(0, 250);
  shade = 0;
  shadeIncrease = -.75;
}