Well, how about going a bit wild and designing a new shape for these twenty eight squares in which the numbers follow on in some way that is not too difficult to follow? For example, you could put the twenty eight squares into a triangle and decide to go in an up-and-down order like this:-
You can then go further by looking at the way the numbers are arranged and see if you can spot any patterns. For example in the first usual way:-
1. If you take any two by two square (like the one in at the top left-hand corner with $1$, $2$, $8$ and $9$ in it), then the opposite corners of that square add up to $10$. Then, if you take the next two by two square along [with $3$, $4$, $10$ and $11$ in] then the opposite corners add up to $14$ and so on.
2. Going down any column the numbers increase by $7$.
Do let us know what you discover in the designs you have created. Can you explain why the patterns occur?
Then ask "I wonder what would happen if ...?''