Read Baldeee's post #3. Try it out. It fulfills - proves - the requirement being asked. That is QED. Your rather hyperbolic* logic contains a series of assumptions and premises that may or may not be granted. Baldeees answer doesn't tell; it shows.
*Why do I say it's hyperbolic? Because you attempt invoke infinities as if they affect the outcome. They don't. Here's an example of an infinity captured in a single entity: "Even numbers. All of them". I can do a lot of things with this entity without caring that it happens to have an infinite number of elements in it. For example: I can divide any element by two and still have an integer. Despite having an infinite number of elements this applies to it does not paralyze me or prevent further work with the set of elements. In other words, I did not have to ... "start by imagining infinity" or "hold it in my head". You are needlessly complicating this, and paralyzing yourself.
-4 is an even number. -4 is an even number exactly like 2 and 4 are both even numbers. There's nothing else to it. There's nothing else to say. EB