Suggestion. Task for 'Iterables' article

It would be useful to have some practice tasks with realization of concepts in article [Iterables](https://javascript.info/iterable).

An idea of task is in the article: "make an iterable object that generates an infinite sequence of pseudorandom numbers".

Possible solution:
```
let randomObj = {
min: 10,
max: 100,
}

randomObj[Symbol.iterator] = function() {
return {
start: this.min,
end: this.max,
next() {
return {
done: false,
value: Math.random() * (this.end - this.start) + this.start,
};
}
}
}

const THRESHOLD = 20;

for (let value of randomObj) {
alert(value); // show random generated value
if (value < THRESHOLD) break;
}
````

Start by reading the linked Iterables article and its existing exercise structure. Use the proposed infinite pseudorandom-number iterable as the task reference, then check how practice tasks are organized elsewhere in the tutorial. Done means the article includes an appropriate practice task with a clear prompt and solution guidance.

Written by the indexing model from the issue text.