char led[] = { 1, 2, 4, 8 };

void delay( void )
{
    char i = 0, j, k;
    while( i++ < 5 )
    {
        j = 0;
        while( j++ < 250 )
        {
            k = 0;
            while( k++ < 250 )
                nop();
        }
    }
}

main()
{
    set_tris_b( 0 );

    char j, i = 0;
    while( 1 )
    {
        output_port_b( ~led[i++] );
        if( i >= 4 ) i = 0;

        j=2;
        while( j-- )
            delay();
    }
}