When to use explicit specifier for multi-argument constructors?

I have recently learned about the explicit specifier.

Suppose we have:

f( W, W, W );

Now if we do

f( 42, 3.14, "seven" );

The compiler will attempt the following implicit conversions:

f( W(42), W(3.14), W("seven") );

If we have defined matching constructors for W, namely:

W(int);
W(double);
W(std::string);

...it will succeed.

However, if we make the first one explicit:

explicit W(int);

... this disables the implicit conversion.

You would now have to write:

f( W(42), 3.14, "seven" );

i.e. it is forcing you to explicitly state the conversion

Now on to the question:

It is possible to write:

explicit W(int,int); // 2 arguments!

This compiles!

But I can't see any corresponding scenario that might require this syntax.

Can anyone provide a minimal example?