Learn Spanish (Latin America): ¡Qué puntada tan perfecta!

In exclamatory sentences following the formula qué + noun + adjective, Spanish uses tan (or sometimes más) to mean 'so' or 'such a.' You cannot use muy in this structure. So, ¡Qué puntada tan perfecta! is the standard way to say 'What a perfect stitch!'

Since this lesson is about lexical reduplication, how could I apply it to this sentence?

You can double the adjective to emphasize the maximum degree of perfection by saying: ¡Qué puntada perfecta perfecta! This repetition tells the listener that you mean the truest, most literal sense of the word—it is completely flawless, not just casually 'great.'

Isn't perfecta already an absolute state? Does it make sense to emphasize it with tan or by repeating it?

Logically, something is either perfect or it isn't. However, in everyday speech, absolute adjectives like perfecto or excelente are often used loosely to just mean 'very good.' Adding tan or using reduplication (perfecta perfecta) restores the word's true, absolute meaning.

Does puntada only refer to a sewing stitch?