Update README.md assignment 3

Author: stef4k

assignment-3/README.md

@@ -24,15 +24,82 @@ The `F` symbol means moving forward, the `+` symbol means turning left 90 degres
 
 <b>F + F − F − F + F</b>
 
-which corresponds to the following figure:
+which corresponds to the following figure:  
+<p align="center">
+<img src="https://github.com/stef4k/Algorithms-and-data-structures-assignments/blob/main/assignment-3/images/koch_curve1.png" width="300" height="300" />
+</p>
 
 If we apply the rule twice, we will get the string:
 
 <b>F + F-F-F + F + F + F-F-F + F-F + F-F-F + F-F + F-F-F + F + F + F-F-F + F + F</b>
 
-This gives us the following figure:
+This gives us the following figure:  
+<p align="center">
+<img src="https://github.com/stef4k/Algorithms-and-data-structures-assignments/blob/main/assignment-3/images/koch_curve2.png" width="400" height="400"  />
+</p>
+
+If we apply the rule five times, we will get a much larger string, with 6,249 characters, which gives us the following shape:  
+
+<p align="center">
+<img src="https://github.com/stef4k/Algorithms-and-data-structures-assignments/blob/main/assignment-3/images/koch_curve5.png" width="600" height="500" />
+</p>
+
+## Installation requirements
+Install the necessary library:  
+
+    pip install matplotlib
+
+## Running the script
+In order to run the script, execute the following command from cmd:  
+
+    python lsystem.py [-m] [-d] <input_file> [output_file]
+
+The program will either edit grammar files or find the grammar that describes a shape. This behavior will be determined by the presence of the -d parameter
+
+## Grammar Editing
+
+Firstly, if the user does not give the -d parameter. Then the <input_file> parameter is the name of the file that contains the L-system grammar and the parameters that will be used. For example for the koch curve, the file is:
+
+    {
+      "axiom" : "F",
+      "left_angle": 90.0,
+      "right_angle": 90.0,
+      "step_length": 5,
+      "order": 5,
+      "start_angle" : 0,    
+      "rules" : {
+        "F": "F+F-F-F+F"
+      }
+    }
+    
+The file contains the following fields:
+* axiom: the axiom
+* left_angle: the angle of the left turn
+* right_angle: the angle of the right turn
+* step_length: the length of the step
+* order: the number of applications of the rules
+* start_angle: the value of the starting angle
+* rules: the rules of grammar
+
+If the parameter -m is given, the program prints the result string as an output. If the user gives the [output_file] parameter, [output_file] is the name of a file to be created. This file will consist of lines. Each line of the file will contain two pairs of coordinates:
+
+`(x1, y1) (x2, y2)`
+
+## Examples
+### Example 1
+
+### Example 2
+
+### Example 3
+
+### Example 4
+
+### Example 5
+
+### Example 6
+
+### Example 7
 
-If we apply the rule five times, we will get a much larger string, with 6,249 characters, which gives us the following shape:
 
 ##
 [Complete Greek assignment description](https://github.com/dmst-algorithms-course/assignment-2019-3/blob/master/assignment_2019_3.ipynb)