For a single pair of left single quotes, ?name is clear:

Any valid Maple name formed without using left single quotes is precisely the same as the name formed by surrounding the name with left single quotes.

So this is fine:

`x`;
                      x

But what about multiple left single quotes? This help page also states:

A name may also be formed by enclosing any sequence of characters in a pair of left single quotes

Any sequence of characters includes a sequence of left single quotes, but another story of parsers occurs.

1D input:

``x``;

Error, missing operator or `;`

```x```;

                      `x`

````x````;

Error, missing operator or `;`

`````x`````;

                      ``x``

Not clear which is the issue here (something about the empty name?).

2D standard input:

``x``;

                        ``^2*x

```x```;

                        ``^2*x

````x````;

                        ``^4*x

`````x`````;

                        ``^4*x

Nice effect (when typeset). A product is implied and the empty name commutes with 'x'. And yet...

2D clasic input:

``x``;

Unable to convert "``x``;" to an expression

```x```;

                        `\`x\``