This example demonstrates JavaScript exception handling and control flow from Chapter 8 of Eloquent JavaScript, using a React starter template. The code implements `reliableMultiply`, which retries a `primitiveMultiply` function that randomly throws a custom `MultiplicatorUnitFailure` error, and `withBoxUnlocked`, which temporarily unlocks a box object, executes a body function, and restores the lock state in a `finally` block. The page renders static HTML with inline CSS and empty script tags, showing error-catching patterns without visual output.