Is there a backward 'Z' in American English?

In footage which I was not able to capture, recently, an American documentary presented an alphabet for teaching to children with a backward 'Z'. That is, the letter was like an 'S' with straight lines.

Was this a mistake or is the backward Z actually used in American English or American dialect ?

The only references I can find are a Stack Exchange question about representing a backward Z as a mathematical symbol and a Wikipedia article (citing no sources) which, tantalisingly, suggests it is part of the ancient Latin alphabet.

Solution 1:

In the Pitman Initial Teaching Alphabet (ITA), a backward 'z' is called 'zess', and is used to denote the hard 's' sound used in many plural forms of nouns and third-person singular present forms of verbs (including is). The ITA is an educational aid, and is not used in normal writing to replace the standard alphabet.

Initial Teaching Alphabet