/*
**************************************
* chunk Function v1.0 *
* Autor: Carlos R. L. Rodrigues *
**************************************
*/
function chunk(a, s){
for(var x, i = 0, c = -1, l = a.length, n = []; i < l; i++)
(x = i % s) ? n[c][x] = a[i] : n[++c] = [a[i]];
return n;
}