“The hard and expensive part of the above one-sentence explanation — the part that we’ve only recently hit on how to do using massive amounts of electricity and

“The hard and expensive part of the above one-sentence explanation — the part that we’ve only recently hit on how to do using massive amounts of electricity and leading-edge computer chips — is hidden deep inside the word /related/.” The whole point of mentioning relatedness is to show readers that we’re not dealing with finite n-grams.