What’s special about each of these sentences? It's different for each sentence.
Easy:
A bad chef, mad like a jackal, made a damaged, half-baked milk cake a mile high.
Tomorrow we’ll see pretty yellow buttercups scattered across sunny green hills.
Your woozy son stoops to put your toy ox up onto your toy zoo.
Hard:
A beefy chimp hops by, almost billowy in his loopy effort.
A nightclub academic stayed late, off dancing with Miami DJ funk.