Can a block be created in less than 3 seconds?

[nullun]

It looks like you’re using the timestamp in each block to work this out. The timestamp is only in whole seconds, so it’s not precise enough to tell you if a block was proposed in 3.5 seconds. Additionally the timestamps are set by the block proposer, but must meet certain criteria. It can be no lower than the previous block’s timestamp, and it can be no more than 25 seconds beyond it. I would also imagine that each computer in the network is likely going to have its own clock skew compared to one another despite NTPs best efforts, so trusting the timestamp as being 100% accurate can’t be guaranteed.