Add Concept exercises

[0xNeshi]

We need to add exercises that help practice existing concepts. These are called Concept exercises, and they're different from Practice exercises in that they are supposed to be super focused on teaching a specific concept, and just that concept (so an exercise tied to felts should force the student to use felts to solve a problem).

---

This is a catch-all issue. Contributors wishing to work on this should post a comment under this issue stating:

1. What exercise you'd like to implement. You can either think of one of your own, but it's best to take inspiration from existing tracks' so-called "stories", read more here https://exercism.org/docs/building/tracks/stories
2. Which concept(s) would this exercise be trying to teach.

Below is a template you can use for these comments:

I wish to implement the following concept exercise:
<-- describe the exercise -->

This exercise would be teaching the following concepts:
<-- list the concepts this exercise would be related to -->

---

See how an existing track implemented Concept Exercises, e.g. Python: https://github.com/exercism/python/tree/main/exercises/concept
https://github.com/exercism/python/blob/main/config.json#L28

[yoyounik]

I wish to implement the following concept exercise:
where i am going to write some code to help me cook a brilliant lasagna from my favorite cooking book.
I have four tasks, all related to the time spent cooking the lasagna.

This exercise would be teaching the following concepts:
basics, variables, functions, integer-introduction, comments, constants, type-annotations in java

[0xNeshi]

Hi @yoyounik , thanks for taking an interest in contributing to open source!

An exercise similar to the one you proposed already exists, but feel free to pick any of the already proposed exercises:
https://github.com/exercism/cairo/issues?q=is%3Aissue+is%3Aopen+add+concept+exercise

Just ping me under the issue you'd like to work on, and I'll assign you

[0xNeshi]

All the language concepts have associated concept exercises, with many only left to be implemented.
Closing this issue as there's no need for additional concept exercises.