For potters, they say that making a teapot is the test of mastery. You have to form the main part, the spout, the lid, and then you have to make sure they fit together. You have to pull a handle and attach it. All the major techniques that a potter can use, are used in a teapot.
For knitters, I think that a cardigan is the equivalent challenge. Very rarely do the knitting patterns include instructions for every single possibility. You have to come up with some solutions on your own. Here are some more technical finishing details for Cityscape.
First off, the buttonholes. I ended up with 134 stitches on the buttonband using my "pick up and REALLY knit" technique that I described two posts back. That means that I needed the same number for the buttonhole band. Although I ended up with 139, I reduced the number by 5 as I worked the first row, by purling two together every so often. The pattern called for 9 buttons "evenly spaced." I believe in evenly spacing the buttonholes, and putting the buttons on last, because buttonholes are much harder to redo than buttons. So I needed to evenly space 9 buttonholes across 134 stitches, with the buttonholes having a value of 3 stitches and the top and bottom buttonholes about 1 inch in from the top and bottom edges of the buttonhole band. I allowed 5 stitches for the top and bottom margins (10 stitches). Nine buttonholes x 3 stitches per = 27 stitches, + 10 margin = 37 stitches. 134 total stitches - 37 stitches = 97 stitches for the 8 intervals between the 9 buttons = 12 stitches per interval, except for the bottom interval where there were 13. See, I CAN do math. I still need to buy buttons, though.