Nursery rhymes often address dubious activities. The young explore ways to engage with circumstances, usually flouting a bunch of rules.
If this poem has a moral, it is beyond Rhino logic. In its favor, it involves a plum and a pie.
One thing Rhinos do not often confront is Corners in the Wild. We have few walls, which are a key ingredient for corners. For Rhinos, corners create misgivings. “Proceed with caution, Mr. Horner.”