int ah = 11; // A high (was Red)
int bh = 10; // B high (was Yellow)
int ch = 9;  // C high (was Blue)
int al = 5;  // A low (was Red)
int bl = 4;  // B low (was Yellow)
int cl = 3;  // C low (was Blue)
int del = 1000;

void setup() {
  pinMode(ah, OUTPUT);
  pinMode(bh, OUTPUT);
  pinMode(ch, OUTPUT);
  pinMode(al, OUTPUT);
  pinMode(bl, OUTPUT);
  pinMode(cl, OUTPUT);
}

void loop() {
  // ah, bl
  digitalWrite(ah, HIGH);
  digitalWrite(bl, HIGH);
  delay(del);
  digitalWrite(bl, LOW);
  delay(del);

  // ah, cl
  digitalWrite(cl, HIGH);
  delay(del);
  digitalWrite(ah, LOW);
  delay(del);

  // bh, cl
  digitalWrite(bh, HIGH);
  delay(del);
  digitalWrite(cl, LOW);
  delay(del);

  // bh, al
  digitalWrite(al, HIGH);
  delay(del);
  digitalWrite(bh, LOW);
  delay(del);

  // ch, al
  digitalWrite(ch, HIGH);
  delay(del);
  digitalWrite(al, LOW);
  delay(del);

  // ch, bl
  digitalWrite(bl, HIGH);
  delay(del);
  digitalWrite(ch, LOW);
  delay(del);
}