"think of" and "think about"

[makone]

Hi,

I would like to ask what the difference between "to think of" and "to think about" is. Thank you for your help in advance.

[Shakespeare's brother]

Makone, I understand that there is no difference; the two are interchangeable:

Think of all the things you could buy

Think about all the things yuo could buy

What do you think about when you walk?

What do you think of when you walk?

etc.