[AshleyGrant]

English is a strange language. "Twice squared" could be interpreted both as "Twice as hard, squared" or "Twice as hard, squared two times."

Think of the sentence, "A man, twice fooled, shall not be fooled again."

[cgriswald]

If x is the difficulty, the phrase either means “twice the difficulty, squared”: (2x)^2 or 4x^2.

Or “the difficulty squared and squared again”: (x^2)^2 or x^4.

The GP is asking why x == 2 in the second example rather than just “the difficulty”. English interpretation doesn’t explain that.