String[] words = {
  "a","b", "c", "d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};

// font for text
PFont myFont;

void setup(){
  size(600,50);  // set applet size
  myFont = loadFont("Crayon-24.vlw"); 
  textFont(myFont); 
  noCursor();  

}

void draw(){
  background(#003C00);
  
  int whichWord = constrain((words.length) * mouseX/width, mouseY/height, words.length-1) ;

  text(words[whichWord], mouseX,mouseY);
}