}
function i4()
{
    echo "i4\n";
    return 0;
}
function i5()
{
    echo "i5\n";
    return 0;
}
function i6()
{
    echo "i6\n";
    return 0;
}
$a = array(array(0));
$b = array(array(1));
$c = array(array(2));
$a[i1()][i2()] = $b[i3()][i4()] = $c[i5()][i6()];
var_dump($a);
var_dump($b);
var_dump($c);
$a[i1()][i2()] = $b[i3()][i4()] = -$c[i5()][i6()];
var_dump($a);
var_dump($b);
var_dump($c);
$a[i1()][i2()] = -($b[i3()][i4()] = +$c[i5()][i6()]);
var_dump($a);
var_dump($b);
var_dump($c);
{
    echo "i2\n";
    return 0;
}
function i3()
{
    echo "i3\n";
    return 0;
}
function i4()
{
    echo "i4\n";
    return 0;
}
function i5()
{
    echo "i5\n";
    return 0;
}
function i6()
{
    echo "i6\n";
    return 0;
}
$a = array(array(0));
$b = array(array(1));
$c = array(array(2));
$a[i1()][i2()] = $b[i3()][i4()] = $c[i5()][i6()];
var_dump($a);
var_dump($b);
var_dump($c);