The purpose of our program is to make a beautiful setting of a city at night. With buildings, windows, stars and the moon. Our program codes work by the computer reading our calls and making the turtle do it. From what I think the most important program features is getting to loop our calls. It's the most important program features in my opinion because it can repeat your calls, how many times you want it to repeat. Like if you write a code to draw a star and you want it to draw like 150 stars you just loop it and it does it. The most difficult programming problem I encountered while writing my individual code, was trying to draw a perfect star. Trying to get all the ends of the lines to meet so that it can make a star because sometimes you'll make a line but it might not touch the other and it will not make a star. I'll just look retarded. But after I got all the ends to meet, I just loop it and it looked like thousands of stars in the sky. An abstraction used in our program was that we had ideas that came together and created something extraordinary and beautiful. The collaboration was very important part of our project. I had problems doing my stars and my partner and I had a collaboration about how I will do it, and at the end, my stars were looking pretty good. The collaboration we used was we brainstormed and shared our ideas before the process of writing code begins. After that, we choose one part off the project and we did it and after we came back and combined it together to build our final project.