It’s become as iconic an image of psychology as Sigmund Freud puffing on a cigar. The Rorschach test, named after creator and psychiatrist Hermann Rorschach, has been allowing people to interpret its abstract inkblot images—and for mental health professionals to draw conclusions about their personalities and possible mental disorders—since its debut in 1921. For a clearer picture, check out some facts about the test’s origins, efficacy, and more.

1. THE RORSCHACH TEST WAS INSPIRED BY A CHILDREN'S GAME.

In the late 19th century there was a popular children's game called klecksography—the art of making images with inkblots. The game generally involved pouring ink onto paper, folding the paper over, and seeing what images emerged. Working in a Swiss asylum, Rorschach wondered if patients would interpret these inkblots differently depending on pathology, which he had some success with. That inspired him to begin using his own custom-made, abstract, symmetrical designs to solicit conceptual answers from his subjects. In doing so, Rorschach believed he could burrow deeper into a patient's subconscious than written psychological tests allowed.

2. WE KNOW NEXT TO NOTHING ABOUT HOW THE RORSCHACH TEST CARDS WERE DESIGNED.

Rorschach first developed the inkblot test of 10 splotchy cards to diagnose mental illness. According to Damion Searls, author of a history of Rorschach and his creation titled The Inkblots, no surviving memos or notes exist that detail Rorschach's process for designing the cards or what data or sources he might have used to craft them. In his later writing, Rorschach said only that "empirical observations" informed the blots and that he had "no explanation for why the test worked at all," according to Searls.

3. RORSCHACH'S COLLEAGUES WEREN'T IMPRESSED.

Although Rorschach was eager to publish the inkblots in 1918 to bring them into wider use, the illustrations were met with derision. Publishers wanted him to pay them to reproduce the cards, possibly owing to wartime paper rationing. Worse, his colleagues didn't believe the blot test had any demonstrable value. After Rorschach published them in his 1921 book, Psychodiagnostics, German psychologists called them "crude." The test didn't receive wide acclaim until it was brought to the United States by child psychologist David Mordecai Levy in 1923—a year after Rorschach died at age 37 from appendicitis.

4. THE RORSCHACH BLOTS ARE VERY DELIBERATELY MESSY.

Rorschach developed the 10 blots with a kind of structured disorder. While the cards appear messy, he felt they couldn't present as deliberately crafted, otherwise patients might think the art was customized for their own specific session. Rorschach also omitted any perceptible brush strokes or other indications they had been handmade.

5. SUBJECTS HAVE THREE REACTIONS.

Typically, people exposed to the Rorschach test are processing each image on three planes: form, movement, and color. They examine the blot’s form, or shape. Some might see a bear; others, a bat. People will also assign varying levels of movement to the shapes. If they see a person, he or she might be dancing. Finally, Rorschach observed how people reacted to the introduction of color in five of the 10 cards. A person's response to the sudden infusion of pigment into the black and white shapes might indicate stronger emotional responses.

6. RORSCHACH THOUGHT THE TEST WOULD WORK ON EVERYONE—EXCEPT TEENAGERS.

Rorschach believed answers to his test could illuminate a subject's psychological state. Creative types might see more images in motion, while those ruminating on details lacked imagination. Depressed persons didn't remark much on the introduction of color, while “neurotics” were said to be alarmed by the sudden explosion of red. The only subjects he felt the test failed to assess were teenagers, since they had too much in common with the clinically insane.

7. THE BLOTS HAVE NEVER CHANGED.

From their initial publication in 1921, the 10 blots designed by Rorschach have never undergone any kind of facelift. Contrary to popular belief, psychologists don't create their own cards. They use Rorschach's, and his 10 images are still the ones in circulation today.

8. THERE'S STILL DISAGREEMENT OVER WHETHER THE TEST ACTUALLY WORKS.

Over the years, the Rorschach test has been shuffled between the shared file drawers of psychology, supported by some therapists and derided by others. Critics say the scoring system and parsing answers is as subjective to the psychologist as it is to the patient and that it’s pseudoscience. A 2000 meta-analysis of available data demonstrated that “the substantial majority of [Rorschach] indexes are not empirically supported.” Other professionals find objective evidence in a more polished scoring system for answers first used in the 1970s and see the test as having value in learning how people express their impressions—while not diagnostic, it can be informative.

9. THEY'RE NOT SUPPOSED TO BE PUBLISHED ONLINE.

Like virtually everything else, the Rorschach test is readily available for online viewing—but the psychologists who still put stock in the test would prefer you didn't look at it. The test is intended to be administered to people who have no prior familiarity with the images, ensuring they don’t create preconceived answers or get a sense of what a "right" answer might be. When the images (and the most commonly-recorded responses) were uploaded to Wikipedia by emergency room physician James Heilman in 2009, the move sparked raging debate in psychology circles. Heilman was unmoved, saying that it was no different from posting an eye exam chart.

If you'd like to occupy your time with a multiple-choice version of the test, there's one available online.