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Code 00:
PFont font;
String letters = "";
int back = 102;
void setup() {
  size(200, 200);
  textAlign(CENTER);
}
void draw() {
  background(back);
  text(letters, 50, 50);
}
void keyPressed() {
  if ((key == ENTER) || (key == RETURN)) {
    letters = letters.toLowerCase();
    println(letters);
   if (letters.equals("black")) {
    back = 0;
  } else if (letters.equals("gray")) {
    back = 204;
  }
    letters = ""; //clear the variable
  } else if ((key > 31) && (key != CODED)) {
    // If the key is alphanumeric, add it to the String
    letters = letters + key;
  }
}
//I will add threads, buttons, and more as I go along.
Answers
http://studio.processingtogether.com/sp/pad/export/ro.9Zo$UbIWYZEDR/latest