var b = require('bonescript');
var state = b.HIGH;
var delay = 500;
b.pinMode('USR0', 'out');
b.pinMode('USR1', 'out');
b.pinMode('USR2', 'out');
b.pinMode('USR3', 'out');

var tab = new Array('USR0', 'USR1', 'USR2', 'USR3');
for(var i = 0; i < tab.length; i++)
{
    b.digitalWrite(tab[i], !state);
}

function led(i, state, inc)
{
    if(i < tab.length && i >= 0)
    {
        console.log('LED: ' + i + ' State: ' + state + ' Inc: ' + inc + ' Delay: ' + delay);
        b.digitalWrite(tab[i], state);
        setTimeout(function(){led(i+inc, state, inc);}, delay);

    }
    else if (i > 0)
    {
        inc*=-1;
        i+=inc;
        state = state ? b.LOW : b.HIGH;
        led(i, state, inc);
    }
    else
    {
        inc*=-1;
        i+=inc;
        state = state ? b.LOW : b.HIGH;
        led(i, state, inc);
    }
}

console.log('Start...');
setTimeout(function(){led(0, state, 1);}, delay);
console.log(delay+ ' more msec...');