size(400,400); // Sets the canvas too 400 x 400 pixels
background(100,0,0);

stroke(255);

int a=10;
do {
  println("a is now: "+a);
  a=a-1;
} while(a>0);

// The above is the same as this:
for(int i=10; i>0; i=i-1) {
  println("i is now: "+i);
}

// Run loop random number of times
int run=0;
do {
  run++;
  println("run "+run+" times");
} while(random(100)>5);


run=0;
while(random(100)>5) {
  run++;
  println("run "+run+" times");
}