Prototype for fancy stair lighting.

StairLighting.pde

int pins[] = {11,10,9};
int SPEED = 255;

int buttonA = 3;
int buttonB = 2;
int buttonStateA = LOW;
int buttonStateB = LOW;
int numleds = sizeof(pins)/sizeof(int);
byte ON = 0;

// toggles LEDs from top to bottom (high pins to low pins)
void t2b() {
  if (ON == 0) {
    for (int x=0;x<numleds;x++) {
      for (int i=0;i<=255;i++) {
        analogWrite(pins[x], i);
        delay(SPEED);
      }
    }
    ON = 1;
  } else {
    for (int x=0;x<numleds;x++) {
      for (int i=255;i>=0;i--) {
        analogWrite(pins[x], i);
        delay(SPEED*2);
      }
    }
    ON = 0;
  }
}

// toggles LEDs from bottom to top (low pins to high pins)
void b2t() {
  if (ON == 0) {
    for (int x=numleds;x>=0;x--) {
      for (int i=0;i<=255;i++) {
        analogWrite(pins[x], i);
        delay(SPEED);
      }
    }
    ON = 1;
  } else {
    for (int x=numleds;x>=0;x--) {
      for (int i=255;i>=0;i--) {
        analogWrite(pins[x], i);
        delay(SPEED*2);
      }
    }
    ON = 0;
  }  
}

void setup() {
  for (int x=0;x<numleds;x++) {
    pinMode(pins[x], OUTPUT);
  }
  pinMode(buttonA, INPUT);
  pinMode(buttonB, INPUT);
  
  // make speed values make more sense
  // higher setting = faster fading
  // tl;dr 1 = 255, 255 = 1
  SPEED = map(SPEED, 1, 255, 255, 1);
}

void loop() {
  // wait for input trigger
  buttonStateA = digitalRead(buttonA);
  buttonStateB = digitalRead(buttonB);
  
  if (buttonStateA == HIGH) {
    t2b();
    delay(2334);
    t2b();
  }
  
  if (buttonStateB == HIGH) {
    b2t();
    delay(2334);
    b2t();
  }
}