   byte digit_value = (number_for_display / digit_scale) % 10;
 
   // push the digit to the LED display
-  pushSegmentRegister(LCD_DIGIT_MASK[digit_value]);
+  pushSegmentRegister(LED_DIGIT_MASK[digit_value]);
   digitalWrite(DIGIT_BASE_PIN + current_digit, HIGH);
 }
 

  0b01111111,
  0b01101111
};

volatile int number_for_display = 0;   // the number we'll display on the LED unit
volatile byte current_digit = 0;       // 0-3 left to right

void setup() {
  Serial.begin(9600); 
  pinMode(ST_CP_LATCH_PIN, OUTPUT);
  pinMode(SH_CP_CLOCK_PIN, OUTPUT);
  pinMode(DS_DATA_PIN, OUTPUT);

#define DIGITS 4

// define the bitmasks for characters 0-9
byte LED_DIGIT_MASK[] = {
  0b00111111,
  0b00000110,
  0b01011011,
