;Task:
Produce a zig-zag array.


A &nbsp; ''zig-zag'' &nbsp; array is a square arrangement of the first &nbsp; <big>N<sup>2</sup></big> &nbsp; natural numbers, &nbsp; where the
<br>numbers increase sequentially as you zig-zag along the array's &nbsp; [https://en.wiktionary.org/wiki/antidiagonal anti-diagonals].

For a graphical representation, see &nbsp; [[wp:Image:JPEG_ZigZag.svg|JPG zigzag]] &nbsp; (JPG uses such arrays to encode images).


For example, given &nbsp; '''5''', &nbsp; produce this array:
<pre>
 0  1  5  6 14
 2  4  7 13 15
 3  8 12 16 21
 9 11 17 20 22
10 18 19 23 24
</pre>


;Related tasks:
* &nbsp; [[Spiral matrix]]
* &nbsp; [[Identity_matrix]]
* &nbsp; [[Ulam_spiral_(for_primes)]]


;See also:
* &nbsp; Wiktionary entry: &nbsp; [https://en.wiktionary.org/wiki/antidiagonal anti-diagonals]
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