Shadowing Practice: The inscribed square problem - Learn English Speaking with Video

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10 sentences
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Here's a question that nobody in the world knows the answer to.
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Suppose you have some closed continuous curve.
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If you can find four points somewhere on this loop that make the vertices of a square, it's called an inscribed square of the loop.
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And the unsolved question is whether every possible closed continuous loop like this necessarily has an inscribed square.
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The question was originally posed by Otto Topolitz in 1911, and it's commonly known as the inscribed square problem.
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One of my all-time favorite pieces of math, easily in the top five, is a very beautiful proof for a simpler version of this question,
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asking instead whether you can necessarily find an inscribed rectangle.
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The argument is originally due to Herbert Vaughn, and as a spoiler, our discussion here is going to lead you to think about this shape right here, what's known as a Klein bottle,
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but it won't come up as some curiosity or a trinket, it arises as a natural problem-solving tool.
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Thank you.

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Why practice speaking with this video?

This video dives into a fascinating mathematical problem known as the inscribed square problem, originally posed by Otto Topolitz in 1911. Engaging with such intellectually stimulating content not only expands your knowledge but also enhances your English speaking practice. By discussing complex ideas, learners can improve their ability to articulate thoughts in English, practice new vocabulary related to mathematics, and develop their overall fluency. The challenging nature of the subject encourages you to think critically and express your understanding, making it an excellent choice for shadow speech exercises. Incorporating this video into your routine creates an opportunity for shadowspeak, where you can mimic the speaker's intonations and styles for a more immersive learning experience.

Grammar & Expressions in Context

  • Conditional Sentences: The phrase "If you can find four points..." uses a conditional structure that is critical for making hypotheses. Practicing this structure helps in forming complex sentences in English.
  • Descriptive Language: Notice the use of descriptors like "closed continuous curve" and "inscribed square." This precise vocabulary allows learners to describe mathematical concepts clearly, an important skill in both speaking and writing.
  • Present Perfect Tense: When the speaker states, "nobody in the world knows the answer to," it exemplifies how the present perfect tense is used to express ongoing relevance. This tense is often tricky for learners but is crucial for conveying present implications of past actions.

Common Pronunciation Traps

As with any advanced topic, there are certain words and phrases that may pose pronunciation challenges. Here are a few to watch out for:

  • Inscribed: This word can often be mispronounced. Make sure to practice saying "in-SCRIBED," placing emphasis on the second syllable.
  • Continuous: The correct pronunciation is "kun-TIN-yoo-us." Note the stress on the second syllable, which may help in mastering its pronunciation during English speaking practice.
  • Klein bottle: This term can be particularly tricky. It is pronounced “KLYNE bottle.” Make sure to familiarize yourself with the "KLYNE" sound, which can easily be confused with other sounds when spoken quickly.

By focusing on these aspects in your practice, whether through shadowing techniques or other methods, you can significantly enhance your English speaking proficiency. Use this video as a guide for both intellectual exploration and pronunciation refinement in your journey to mastering the language.

Grammar in this video

The structures the speaker uses most, with the exact words from the video:

StructureIn the video
Passive voice be + past participle — the focus is on what happens, not who does itwas originally posed

What is the Shadowing Technique?

Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.

Shadowing technique: read the full step-by-step guide →