// a repeat loop is a control structure 

// a conditional statement is a control structure . the code runs once 

// if the condition is true

// the control structure of a loop is written just like the if statements

// but wiht a different keyword besides if, while. while this boolean

//statement is true continue to do this code over and over and over

//again. watchout! its possible your program could get stuck inside 

//the loop

//global variables: i can use them anywhere in my code

//local variable: a variable inside a function 

// the while loop has 3 elements: the first one is we start with 

//initializing a variable: var x =0;

//the second thing is we test for an exit condition: x<=width

// the third thing is we have this incrementation operation  x= x+50

// those 3 elements are so common in loops that there is an entire 

//other looping structure called a for loop that condenses the elemntss

//x = x+50 is so common it can be written in shorthand as x+=50

//x = x+1   shorthand is x++

function setup() {

  createCanvas(600, 400);

}

​

function draw() {

  var x = 0;

  background(0);

  strokeWeight(4);

  stroke(255);

​

  while (x <= width) {

    fill( 0,200,255);

    ellipse(x, 100, 25, 25);

    x = x + 50;

  }

  for (var x = 0; x<=width; x=x+50) {

     fill( 155,200,0);

    ellipse(x,300,25,25);

  }

}