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This single line of bash code will crash your system:

:(){ : | : &};:

It is a so-called fork bomb, duplicating itself with each call, eventually draining system resources dry.

Here is how it works, character by character.

:(){ : | : &};:

It is a so-called fork bomb, duplicating itself with each call, eventually draining system resources dry.

Here is how it works, character by character.

In bash, functions are defined with the syntax

foo() {

# function body

}

Using this syntax, the fork bomb first defines the function `:`, then calls itself.

foo() {

# function body

}

Using this syntax, the fork bomb first defines the function `:`, then calls itself.

Thus, we have

:() {

: | : &

}

What is happening inside the function? There are two symbols here that need explaining: `|` and `&`.

:() {

: | : &

}

What is happening inside the function? There are two symbols here that need explaining: `|` and `&`.

This is not a trick: the cosine of the imaginary number 𝑖 is (e⁻¹ + e)/2.

How on Earth does this follow from the definition of the cosine? No matter how hard you try, you cannot construct a right triangle with an angle 𝑖. What kind of sorcery is this?

Read on to find out.

How on Earth does this follow from the definition of the cosine? No matter how hard you try, you cannot construct a right triangle with an angle 𝑖. What kind of sorcery is this?

Read on to find out.

What is common in Fourier series and the Cartesian coordinate system?

More than you think: they are (almost) the same.

Let me explain why!

More than you think: they are (almost) the same.

Let me explain why!

This will surprise you: sine and cosine are orthogonal to each other.

What does orthogonality even mean for functions? In this thread, we'll use the superpower of abstraction to go far beyond our intuition.

We'll also revolutionize science on the way.

What does orthogonality even mean for functions? In this thread, we'll use the superpower of abstraction to go far beyond our intuition.

We'll also revolutionize science on the way.

Our journey ahead has three milestones. We'll

1. generalize the concept of a vector,

2. show what angles really are,

3. and see what functions have to do with all this.

Here we go!

1. generalize the concept of a vector,

2. show what angles really are,

3. and see what functions have to do with all this.

Here we go!

If it is raining, the sidewalk is wet.

If the sidewalk is wet, is it raining? Not necessarily. Yet, we are inclined to think so. This is a preposterously common logical fallacy called "affirming the consequent".

However, it is not totally wrong. Why? Enter the Bayes theorem.

If the sidewalk is wet, is it raining? Not necessarily. Yet, we are inclined to think so. This is a preposterously common logical fallacy called "affirming the consequent".

However, it is not totally wrong. Why? Enter the Bayes theorem.

Propositions of the form "if A, then B" are called implications.

They are written as "A → B", and they form the bulk of our scientific knowledge.

Say, "if X is a closed system, then the entropy of X cannot decrease" is the 2nd law of thermodynamics.

They are written as "A → B", and they form the bulk of our scientific knowledge.

Say, "if X is a closed system, then the entropy of X cannot decrease" is the 2nd law of thermodynamics.

In the implication A → B, the proposition A is called "premise", while B is called the "conclusion".

The premise implies the conclusion, but not the other way around.

If you observe a wet sidewalk, it is not necessarily raining. Someone might have spilled a barrel of water.

The premise implies the conclusion, but not the other way around.

If you observe a wet sidewalk, it is not necessarily raining. Someone might have spilled a barrel of water.

Matrix multiplication is not easy to understand.

Even looking at the definition used to make me sweat, let alone trying to comprehend the pattern. Yet, there is a stunningly simple explanation behind it.

Let's pull back the curtain!

Even looking at the definition used to make me sweat, let alone trying to comprehend the pattern. Yet, there is a stunningly simple explanation behind it.

Let's pull back the curtain!