Please reference the illustration at: screenshots<dot>firefox<dot>com/kBXqJ4tycTCPwjUw/brilliant<dot>org to answer the following question:

Question

On the edge of a wall, you build a brick tower that only holds because of the bricks' own weight. Your goal is to build a stable tower whose overhang d is greater than the length l of a single brick. What is the minimum number of bricks you need?

Note: Each brick has the same mass m and uniform density. There is only one brick per layer. No gluing is allowed.

2 bricks
3 bricks
4 bricks
5 bricks
6 bricks
It's impossible without gluing the bricks together

Answer 1

Four brick