     // clears the screen:
     // (1 << 8) & 0xff = 0 -> clear screen
     // in that situation the last row won't stay lit permanently, but will
-    // obey DUTY_CYCLE_MILLIS
+    // obey DISPLAY_MILLIS
     //
     for(size_t i = 0; i < countof(ScreenRows) + 1; ++i) {
         // Take the latchPin low so the LEDs don't change while you're sending in bits:


        // Take the latch pin high so the LEDs will light up:
        digitalWrite(LATCH_PIN, HIGH);
//
//         delay(1);
    }
}



static const int buttons[] = { BUTTON_1_PIN, BUTTON_2_PIN, BUTTON_3_PIN, BUTTON_4_PIN };
static ClockState clockState;
static unsigned long lastDisplayMillis     = 0;
static unsigned long lastClockUpdateMillis = 0;

static void display()
{
