Challenge 2: A Binding to undefined That's Never Forced — Possible Solution
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GHCi session:

    Prelude> let result = let danger = undefined in 42
    Prelude> result
    42

Explanation:
`danger` is bound to undefined, a value that would throw an exception
the instant anything actually forces it. But the body of the let
expression -- the final `42` -- never references `danger` at all.
Because Haskell only evaluates what's actually demanded, and nothing
ever demands `danger`'s value, the binding simply sits there,
unforced, forever. Evaluating `result` only needs to know the value
of `42` itself, which requires no knowledge of `danger` whatsoever, so
the expression succeeds cleanly with no error at all.

WHY THIS WORKS AS AN ANSWER
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This reproduces the chapter's own `let x = undefined in 5` example
with a renamed binding for clarity, confirming that a completely
unused undefined binding never surfaces as an error, exactly the
bottom-never-detonating behavior the chapter describes.