void setup()
{
 DDRD = B11111111;    // Set PORT D as OUTPUT

 DDRB = B00000000;    // Set PORT B as INPUT
 PORTB = B00001111;   // Set bits 0 - 4 to PULL-UP
 
}


void RunnigLEDLeft()          // Effect: Runnig ligth from right to left
{
  byte Operand1 = B00000001;  // Set start bit
   
  PORTD = Operand1;           // Write to port D
 
  for (int cyklus = 0; cyklus<=8; cyklus++)  // 8 LED - so... 8 steps :)
  {
    PORTD = Operand1;           // Write to port D
    Operand1 = Operand1 << 1;   // Shift to LEFT (move ligth to left)
    delay(500);                 // wait..
  }
}

void RunnigLEDRight()               // Effect: Runnig light from left to right
{
  byte Operand1 = B10000000;        // Set start bit

  PORTD = Operand1;                 // Write to port D
 
  for (int cyklus = 0; cyklus<=8; cyklus++)  // 8 LED....
  {
    PORTD = Operand1;               // Write to port D
    Operand1 = Operand1 >> 1;       // Shift bits from left to right
    delay(500);                     // ... and wait...
  }
}

void RunnigDark()                   // Effect: Runnig "dark"
{
  byte Operand1 = B11111110;        // Set start bits
  byte Operand2 = B00000001;        // Set 2nd operand for some bits operation
 
  PORTD = Operand1;                 // Write to port D
 
  for (int cyklus = 0; cyklus<=8; cyklus++) // 8 LED... you know ;)
  {
    PORTD = Operand1;               // Write to port D
    Operand1 = Operand1 << 1;       // Shift bits to LEFT
    Operand1 = Operand1 | Operand2; // Some "bits magic"? No :) Just add one bit to right (OR)   
    delay(500);                     //... aaaaand Wait...
  }
}

void FillLED()                  // Effect: Fill every LED from right to left.
{
  byte Operand1 = B00000001;    // Set start bits
  byte Operand2 = B00000001;    // Set bits for bit logic
 
  PORTD = Operand1;             // Write to port D
 
  for (int cyklus = 0; cyklus<=8; cyklus++) // 8 Led...
  {
    PORTD = Operand1;               // Write to port D
    Operand1 = Operand1 << 1;       // Shift bits to LEFT
    Operand1 = Operand1 | Operand2; // Add bit to LEFT....
   
    delay(500);                     // wait...
  }
}


void loop()             // Main loop
{
  int hodnota = PINB;  // Read port B to hodnota
  
  hodnota = ~hodnota;  // bitwise NOT - pull-up - default value is HIGH ;) 
  hodnota = hodnota & B00001111;  // Mask higher 4 bits
  

  switch (hodnota)          // Test value
  {
    case 1:                 // Button 1
     RunnigLEDLeft();       // Call effect 1
    break;
    case 2:                 // Button 1
     RunnigLEDRight();      // Call effect 2
    break;
    case 4:                 // Button 1
     RunnigDark();          // Call effect 3
    break;
    case 8:                 // Button 1
     FillLED();             // Call effect 4
    break;
    default:                
     PORTD = 0;             // in other case - set PORTD to 0
    break;
  }
 
}