If a significant amount of hashing power leaves the 148BTC chain towards the beginning or middle of a difficulty period, the 148BTC chain's block creation rate (and in turn, transaction confirmations) would slow to a crawl. (wirexapp.com)
In the middle of these difficulties, like the Great Depression of the 1930s, people looked on schools as part of the solution, not as the major part of the problem. (gse.harvard.edu)
For the most part I'd say the new levels are about in the middle of the difficulty level, but a couple of them took quite a bit longer to figure out. (andymerrill.com)