Coding 101 Exam - 26 March 2016 - Задача 05 - Пеперуда

$num = intval(readline());
for ($i = 0; $i < $num - 3; $i++) {
    $i & 1 ? $char = "-" : $char = "*";
    echo str_repeat($char, $num - 2) . "\\" . ' /' . str_repeat($char, $num - 2) . "\n";
}
echo str_repeat('*', $num - 2) . "\\" . ' /' . str_repeat('*', $num - 2) . "\n";
echo str_repeat(' ', $num - 1) . '@' . str_repeat(' ', $num - 1) . "\n";
echo str_repeat('*', $num - 2) . '/' . " \\" . str_repeat('*', $num - 2) . "\n";
for ($i = 0; $i < $num - 3; $i++) {
    $i & 1 ? $char = "*" : $char = "-";
    echo str_repeat($char, $num - 2) . '/' . " \\" . str_repeat($char, $num - 2) . "\n";
}