void setup() {
	for (int i = 0; i < 8; ++i) pinMode(i, OUTPUT);
	analogReadResolution(8);
}

void loop() {
	int len = 0;
	int seq[1000];
	while (len < 3) seq[len++] = random(0, 4); // generate 3 random numbers
	while (1) {
		seq[len++] = random(0, 4); // generate another random number
		for (int i = 0; i < len; ++i) { // flash the LEDs according to seq
			digitalWrite(2*seq[i], HIGH);
			delay(500);
			digitalWrite(2*seq[i], LOW);
			delay(500);
		}
		for (int i = 0; i < len; ++i) {
			while (analogRead(A0) < 240 && analogRead(A1) < 240 && analogRead(A2) < 240 && analogRead(A3) < 240); // wait for press
			for (int j = 0; j < 4; ++j) // check which button was pressed and whether it matches seq
				if (analogRead(A0+j) > 240 && seq[i] != j) goto DONE; // Legit use case of goto to jump out of 3 loops
			delay(250);
		}
		for (int i = 0; i < 8; ++i) { // flash green lights 4 times
			for (int j = 0; j < 4; ++j) digitalWrite(2*j, (i+1)%2);
			delay(100);
		}
	}
	DONE:
	for (int i = 0; i < 2; ++i) { // flash red lights 4 times
		for (int j = 0; j < 2; ++j) digitalWrite(2*j, 1);
		delay(500);
		for (int j = 0; j < 2; ++j) digitalWrite(2*j, 0);
		delay(500);
		for (int j = 2; j < 4; ++j) digitalWrite(2*j, 1);
		delay(500);
		for (int j = 2; j < 4; ++j) digitalWrite(2*j, 0);
		delay(500);
	}
	delay(1000);
}