One of the most important collections to be included in Pharo is the tree data structure and its variants. Here we give a brief introduction to rooted trees that we will build upon in the remainder of this Summer of Code. Main references for this part will be the following two books - “Introduction to Algorithms”, Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, Clifford Stein and “Algorithms”, Robert Sedgewick and Kevin Wayne.
This was an exciting week. I finished the implementation of my first layout. 
Let us continue with exploring graphs. By now we understand the basics, so we will go a step further. One of the reasons why, by using graphs we can accomplish so much, is that graphs have a set of algorithms for traversing them, two of which are especially well known, BFS and DFS.
First, we explain what traversing means.
The word definition is: travel across or through. In the context of graphs, traversing means moving through the graph, visiting nodes (vertices) by using the edges.
During second week of GSoC 2019 coding period on Pharo project, I was learning more about existing implementations of Ordered dictionaries, comparing them and polishing Containers-OrderPreservingDictionary a little bit.
First couple of weeks I have been focused on Pharo. Its syntax, environment and connections. Which has been very helpful, for the implementation part of my project.
Now it is time to switch to other big part, and that is Graphs. Since they are central structure on which my whole project stands on, it is important to have a good understanding of them.
Nina MedićHi, my name is Nina and I am a master student of Computer Science in Novi Sad, Serbia. As a part in one of my classes I was introduced to Pharo world. The simplicity of the language and user friendly environment invited me to explore it more. Now I am a member of Pharo community and the team that is working on improving it.
Smiljana KneževHi, my name is Smiljana Knežev and I am a final year undergraduate student at the Faculty of Sciences, University of Novi Sad. I am doing my studies in Informatics - Information Technologies, and I am very interested in Objected-Oriented design and functional and distributed programming. I am very passionate about Pharo and theoretical computer science and find it very interesting.