Ok, i am new to this and i'm trying to make a real simple project just to test my ability. I just came up with this schema in mind and i don't really know if it's a pattern or something and i'd like to get some suggestions about it and how to improve it.

index.php  # This manage the $_GET['page'] var and load some basic stuff
app/  # Here's the logic part, the pages included in index.php, they do some stuffs and then call templates to output the HTML page
config/  # Here we put some configurations file such as database.con.php or board.con.php which contain an extension or the array $cf
lang/  # Same way of configurations, we have something like en.lang.php or it.lang.php and inside there is an array called $lang 
lib/class/  # Contains all the classes
lib/set/ # Contains sets of functions, such as error.set.php or file.set.php
theme/ # Contains template file that got called from app files

Ben bu şema ile sıkışmış olacak? Geliştirilebilir bir şey değişti / var mı?