How to make walls?

Hey!
Is it possible to make walls (in code)?

hey, thank you for supporting MAKERbuino.

Can you please give us an example of your existing code and more detail on what you want to do?

Thanks

For example, like in Undertale; 2d world, walls (thru you can’t walk), objects (with which you can interact). And world where you have that specific type of travelling (world map is segmented on ‘screens’). How to do that all?
Thanks ;>