In Chapter 53 of Dan Brown's latest novel, "Inferno", Robert Langdon and Sienna Brooks find themselves at The Baptistry of San Giovani in Florence.
Brown describes it like this:
"Adorned in the same polychromatic facing stones and striped pilasters as the cathedral, the baptistry distinguished itself from the larger building by its striking shape - a perfect octagon. Resembling a layer cake, some had claimed, the eight-sided structure consisted of three distinct tiers that ascended to a shallow white roof."
Here is a picture of the Baptistry of San Giovani:
And here's a layer cake:
And this is a traditional Sarawak layer cake:
I say that is quite an accurate comparison!