Using Polish Expressions on a Query Engine?

Polish expressions are expressions of what you want to do, which are grown and paralyzed on a query engine. So an expression takes a series and produces a series. And because the input is the same as the output, you can combine them. That's pretty interesting. There's just a whole bunch of how do I, how can I rather bunch of neat things? What else would you like to highlight here? The most important thing is I want to touch on this expression API.