This is my first weekly challenge submission. Here is my solution, a bit basic, but it gets the job done. It is very instructive to be able to see how others solved the same problem.
I see how the posted solution is more efficient in terms of getting there in fewer steps. I used Cleanse and the DateTime tool (2 steps) while the posted solution accomplished the same thing in just one step by converting two separate fields with just one (Formula) tool. I see the power of the Formula tool in that by nesting functions one can take multiple actions on a single field at once rather than have to have multiple tools in succession accomplish the same thing. I can see how mastery of the Formula tool and the embedded functions can be leveraged to make one's workflows much more efficient.
I think doing this as more steps using just the basic tool functionality without customized Formula functions is more straight forward and easier for a newer (or less technical) person to follow along at the cost perhaps of some inefficiency (extra operations). Perhaps not an issue when dealing with such a small amount of data but could make a difference on a large dataset.
One thing I think the posted solution is missing however is matching the field length (53) of the final output of the variable string Poem field, which is why I added the Auto Field tool.