Nine boxes, two questions
An alignment chart sorts everyone into nine boxes using two questions. The first is how you treat rules: do you follow them (lawful), use them when they help (neutral), or treat them as obstacles (chaotic)? The second is whose interests come first: other people's (good), a fair mix (neutral), or your own (evil). Cross the two and you get nine combinations, from Lawful Good, who returns every shopping cart in the lot, to Chaotic Evil, who rides one across it.
Where the chart came from
The grid started as a game rule. When Dungeons & Dragons came out in 1974, characters had one of three alignments: law, neutrality, or chaos. By the end of the decade, Advanced Dungeons & Dragons had added a second axis, good versus evil, and the nine-box chart was born. Players used it to decide how their characters would behave at the table. The internet later turned it into a meme, and now people sort sandwiches, cartoon characters, and their coworkers into the same nine boxes.
A crosswalk, a coworker, and a shopping cart
Half of the sixteen questions are about rules: an empty street at 2 a.m., a recipe, a policy nobody can explain. The other half are about other people: a coworker who takes credit, a ticket someone dropped, a secret you weren't supposed to hear. Your answers on the first half place you on the lawful-to-chaotic line, your answers on the second half place you on the good-to-evil line, and where the two meet is your box. None of the answers mentions an alignment by name. It takes about three minutes, and there's no sign-up.
What "evil" means on this chart
In the game's sense, evil doesn't mean cruel. It means you tend to put your own interests first, which plenty of perfectly decent people do at the self-checkout. Chaotic doesn't mean reckless either; it mostly means you don't enjoy being told what to do. Good and lawful aren't gold stars, and they come with their own blind spots. Each result page covers what your alignment is good at, where it causes trouble, and which box you work best with.