If you’re beginning to learn Objective-C like I am, things like this aren’t immediately obvious. I was trying to fool around with creating my own class, and I kept getting this warning
warning: no '-blah blah blah' method found along with an accompanying
warning: 'ClassName' may not respond to '-blah blah blah'
The really annoying part was that, despite these warnings, the code still worked just fine. Turns out, my issue was that I had this method in my class implementation (PolygonShape.m):