int grn = 3;
int blu = 4;
int org = 5;
int wht = 6;
int swtch = 7;
int i;

void clear() {
  digitalWrite(grn, 0);
  digitalWrite(blu, 0);
  digitalWrite(org, 0);
  digitalWrite(wht, 0);
  digitalWrite(swtch, 0);
}

void setup() {
  pinMode(grn, OUTPUT);
  pinMode(blu, OUTPUT);
  pinMode(org, OUTPUT);
  pinMode(wht, OUTPUT);
  pinMode(swtch, INPUT);
  clear();
}

bool lckd = false;

void loop() {
  for (i = 6; i > 2; i--) {
    do {
      if (digitalRead(swtch) == 1) {
        lckd = not lckd;
        delay(500);
      }
    }
    while (lckd);
    
    digitalWrite(i, 1);
    delay(100);
  }
  for (i; i < 7; i++) {
    do {
      if (digitalRead(swtch) == 1) {
        lckd = not lckd;
        delay(500);
      }
    }
    while (lckd);

    digitalWrite(i, 0);
    delay(100);
  }
  delay(250);
}