After tackling complex stations like Times Square and Herald Square, the 23rd Street station becomes relatively easy to survey and draw because it only has one line and therefore one level underground. Instead of going back and forth, I sketched out the whole station after one visit and it looks like this:
What is worth mentioning is that it is one of those stations that does NOT let you transfer between uptown and downtown trains inside the station. If you realized you need to reverse your direction of travel, you either have to leave the station, go across the street and swipe (and pay if you don't have a pass) again, or, you have to take the train to a station that does let you transfer and go back.
Of course, it does say so on the sign, that it's for "Uptown and Queens" only. But I think there should be a symbol for, and a term that describes, such stations. I would like to coin the term "SPLIT" here:
split
noun
- A subway station in NYC inside which you cannot transfer between uptown and downtown trains.