Just to be clear, the paper is about an extension to Cuckoo hashing, while the link to the visualization is about standard Cuckoo hashing.

From the paper: "we describe algorithmical changes to cuckoo hash tables allowing a more efficient implementation. More precisely, our hash table adds a bloom filter in each bucket that allows to prune unnecessary lookups to the secondary bucket."

Also, when the paper says "cuckoo hashing" they mean "bucketized cuckoo hashing" which is different enough from the academic description of cuckoo hashing, which is what is described in GP's link, as to be a bit confusing!

So we’re back to trading time for space again? I thought the whole point of a ... oh nevermind.

Yes, I should have been clearer