[PaulBGD_]

Nano basically just uses a block lattice, which looks like a blockchain for each individual user. Blocks are broadcasted across the network and confirmed when you receive the block, and ask the representatives to vote on if the block is legit. Representatives are chosen by users, with the reps having the highest Nano backing being chosen. This gives a network setup where once the block is broadcasted, asking the peer if it's good is the only delay. There is a small PoW on each block, which is to stop blocks from being spammed against the network (however it can be precomputed..)

Disclaimer: built some apps on top of Nano, decently pleasant experience. I keep up a bit with the development of the node software.