We Spread

this was... surreal.

I spent a lot of time debating over the ending. A few hours on Reddit included, I've decided that the mural on the ceiling was Penny committing suicide. Someone pointed out symbolism of the couple times Penny is touching lightbulbs on the ceiling as symbolism for “ideas about suicide” and it made the most sense to me. Someone also more elegantly pointed out that the last couple pages tied into all the math equations Hilbert was mentioning and Penny's conclusion in her body and mind after committing suicide, a sense of finality.

Reading this book will make you feel like you, yourself, are old and losing your memory. Iain Reid perfectly wrote this to make it seem like you and Penny are one and the same. Which adds into how surreal it all is, as “one and the same” being the main plot points throughout this.