Find the Shape Group That Fills the Empty Cell in a 3×3 Grid

What was yesterday's answer?

Quiz 2 was about fixing three sock drawers whose labels were all wrong. The answer is one sock from the drawer labeled "Mixed."

1. The "Mixed" label is wrong too, so that drawer holds only black socks or only white socks. One sock tells you which.
2. If the sock you pulled out is black, that drawer is the black socks drawer.
3. The drawer labeled "White socks" cannot hold white socks, and the black socks drawer is already settled, so it is the mixed drawer.
4. The remaining drawer, labeled "Black socks," is the white socks drawer. If a white sock comes out instead, the same method works.

What is today's puzzle?

In the 3×3 grid below, find the group of shapes that goes where the question mark is.

• Choices: ① ■ ② ■■ ③ ■■■ ④ ▲▲
• Difficulty: ★★☆☆☆
• Suggested time: 3 minutes

Where should you start?

First, see how the type of shape is decided within a row. Then count the shapes in each row and each column and write the counts down. Check both the row direction and the column direction, and the answer narrows to one.

When can you check the answer?

The answer and explanation go up tomorrow (October 16) morning, at the very top of the Quiz 4 post. Write down your choice number and your reason, and compare them tomorrow.

Why do shape pattern puzzles come up so often?

Mensa Korea describes its online brain test as looking at pattern recognition, logical thinking, and overall cognitive ability (checked 2026-10-13). Puzzles about the rule behind shapes in a grid lean on pattern perception rather than language or arithmetic skill, so they are often used to practice this type. Mensa International's standard for joining is a top 2% score on an approved intelligence test, and this puzzle is for practice, not that test.