Open/Close:  

Open for expansion but closed for update.

Ex: Some pega OOTB rules we cannot update them, but we can save as same rule in our ruleset and expand them as per our need.

Liskov Substitution:

as per the LSA training - objects that reference other objects by their base class need not be aware how that class has been extended

ex:

if we create an object named vehical ->(moves, wheels,fuleNeeded)

now if we extend car object from vehicalà car object still holds all the details of vehical object