#define ds 2
#define clk 4
#define latch 3

void setup() {
  pinMode(ds, OUTPUT);
  pinMode(clk, OUTPUT);
  pinMode(latch, OUTPUT);

}
bool a=1;
int mode = 0;
int i;bool b;
void loop() {
  if(mode==0)for( i=0;i<=15;i++){setLed(i,a);delay(100);}
  if(mode==1)for( i=0;i<=7;i++){setLed(i,a);setLed(15-i,a);delay(100);}
  if(mode==2)for( i=7;i>=0;i--){setLed(i,a);setLed(15-i,a);delay(100);}
  a =!a;
 mode = mode>3?0:mode+1;
 setAll(0); 
 a=1;
}

void shiftOut(char val)
{
  for (char i = 0; i <8; i++)  {
    digitalWrite(ds, !!(val & (1 << (7 - i))));
    digitalWrite(clk, HIGH);
    digitalWrite(clk, LOW);
  }
}


char byte1, byte2;
#define setbit(x,y) x|= (1<<y)
#define clearbit(x,y) x&= ~(1<<y)

void setLed(char index, bool level) {
  if (index < 8)
    //byte1=write(byte1 ,index,level);
    if(level)setbit(byte1,index);
    else clearbit(byte1,index);
  else
    //byte2=write(byte2,index, level);
    if(level)setbit(byte2,index-8);
    else clearbit(byte2,index-8);

    digitalWrite(latch,0);
    shiftOut(byte1);
    shiftOut(byte2);

    digitalWrite(latch,1);
}
void setAll(bool l){
  byte1 = l?255:0;
  byte2=byte1;
  digitalWrite(latch,0);
    shiftOut(byte1);
    shiftOut(byte2);
  digitalWrite(latch,1);
}