var a = [[1, 2, 1, 24], [8, 11, 9, 4], [7, 0, 7, 27], [7, 4, 28, 14], [3, 10,
26, 7]];

console.log(a);

for(var i =0 ; i<a.length ; i++)
{
    for(var j =0 ; j<i ; j++)
    {
        
    console.log('Row '+j);
    var ar = a[j].pop();
    console.log(ar);
    }
}