//
// This program controls the brightness of 16 LEDs on a scale from 0 to 15.
// As the pattern moves right to left (or clockwise if the LEDs are arranged
// in a circle, the brightest LED is at the front, and subsequent LEDs are
// each one step dimmer, like the tail of a comet.
//

unsigned char values[16] = { 0, 1, 3, 6, 10, 15, 21, 27, 34, 41, 50, 58, 68, 78, 88, 99 };
unsigned int index = 0;
unsigned int shift = 0;
int cnt = 0;

void
setup()
{                
  P1DIR = 0b11111111;
  P2DIR = 0b11111111;
  P1OUT = 0;
  P2OUT = 0;
}

void
loop()
{
  for( int x = 0; x < 200; x++ )
  {
    int lights = 0;
    for( char y = 0; y < 16; y++ )
    {
      if( x < values[(y+shift)&0b1111] )
      {
        lights |= 1 << y;
      }
    }
    P1OUT = lights;
    P2OUT = lights >> 8;
  }
  if( cnt++ > 10 )
  {
    shift--;
    cnt = 0;
  }
}