Exercises and tests are not the same. But they’re often conflated with regards to creativity. So, it’s important to know the difference between creative tests and creative exercises.
When you’re looking to test your creative thinking, certainly. Or when you’re asked to prove your creative potential, most definitely. Amiright, Giotto?
Giotto di Bondone: “Hellz yeah...”
Right on. See, my man Giotto here (who’s actually dead at the moment) was once asked to demonstrate his artistic skill to the Pope. And he did so by drawing a perfect circle, freehand.
Giotto di Bondone:

And I’m sure glad he did. Because one of the many ways you can test your creative thinking is called the 30 Circles Test, to which we’ll now gracefully segue like a bulldozer merging into rush hour traffic.

This version of the test is from IDEO. They actually call it the 30 Circles exercise. But, if you're like me, you tend to see exercises as tests. Sometimes. Most times, in a quiet, secret, not-really-productive sort of way.
You should give it a go. You get 3 minutes (no cheating!) to turn as many of the circles into as many different things as possible.
BONUS: If you want to know what it feels like to be creative in an agency that isn't IDEO, spend the entire 3 minutes doing things with the circles you love and are very proud of. After the 3 minutes is up, remove a piece of your soul and use it to pay someone to throw you work in the garbage without looking at it and tell you to start over. (Alternatively, go apply at IDEO, where they talk about the 3 minutes you put your heart into as a means of building creative confidence. Bless them. Too bad they aren't more successful.)
For people who aren't like me (e.g. smart folks who aren’t counter-productively self-competitive), I do agree 30 Circles makes for more of an exercise. And this is due to one cognitive bias in particular and all grilled cheese sandwiches in general.
Functional fixedness is, to varying degrees, the resistance to thinking of something doing something other than it is "meant" to do. This bias can even be in play for items that are "meant" to do many things. Butter, for instance.
One use of butter is to ensure the bread of a given grilled cheese sandwich toasts up nice and golden brown. This effect is critical to grilled-cheesery, as science has shown sight (along with smell) play as much a role in how we think things taste than our ability to tastes does.
Butter can be hard to spread though. ESPECIALLY when you store it in the fridge and always forget to take it out in time to make the pile of grilled cheese sandwiches you need to make ASAP to eat up all your feelings with.
Know what the better overall solve is?
Mayonnaise.
Yes. I'm serious. And no, I don't mean Miracle Whip.
Mayonnaise.
Mayo spreads easy right out the jar. Spreading a thin layer on both soon-to-pan-facing sides of your bread results in beautiful, even browning. And you can't taste it. Not one bit.
But there is a decent chance you in your mind just went OH MAH GOD MAYONNAISE ON GRILLED CHEESE EWW THAT IS SO GROSS JUST EWW
Awww. Don't worry, if you did you're like everyone I've ever suggested it to at parties.
Giotto di Bondone: "Why are you going around giving grilled cheese making tips at parties?"
You be dead now. That's not the point.
The point is that if your goal is making the best grilled cheese possible, mayo's better than butter. And if you can't see your way to that you're dealing with some functional fixedness.
And that point is my attempt to point out why 30 Circles is more of an exercise. Circles are shapes. Shapes are symbols. And symbols are abstractions.
So, while imaging a circle can be a tire but also an orange but also a donut is good creative practice, it's not really a test of anything.
Yes. You’re being creative, but there’s no creative problem to solve.
Unless you can't do that. Which would mean something else. Or, unless you thought to the thing with the circle as tire idea that I didn't think to do when I did the 30 Circles exercise. Which means you're some wonderful sort of smug twit.
Remember functional fixedness? For a better way to test your creative replace those 30 Circles with One Brick. Because, unlike the abstraction that is a circle, a brick (a pen is commonly used as well) is made with a specific purpose in mind.
If you actually did spend 3 minutes on 30 Circles try, instead, 3 minutes thinking up as many different uses for a brick as possible. If you want to make the test harder, try to make those uses as varied as possible. (i.e., no "Building a house...building an office, building a wall, building a wall in a field in Shropshire...etc.)
Once done, focus less on how many uses you came up with and more on how it did or didn't feel compared to the 30 Circles exercise.
Because, just now, having to box around your functional fixedness means you had a creative problem to solve. Meaning, as a means of testing your creative I believe the brick makes for the better creative test. Which, btw, means I'M a smug twit, at least according to actor and writer Mallory Cooper, whose post I happened across while researching my own here.
To each their own though, right? This is all food for thought. And, speaking of, high time I kick-off to the kitchen.
All these feelings aren't going to eat themselves up.