The Square Fort
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In Pakistan and in the subcontinent in general there are two major designs of forts which are seen in 90% of the cases.
One of them is the simple, square fort, which usually starts in size from 20m across to all the way to 200m or more.

The extreme case is certainly Pathargarh in India which is 600m across (1).
These forts are almost always built in the plains where there are little other geographical features to make use of. Their simple design makes them cheap and quick to construct.

These would often be used as simple garrisons or as posts on royal roads.
Most weren't use for residential purpose but some like Satghara, Okara (2) do house a permanent population.

Many forts had a barbican which is a walled courtyard before the main entrance to make the defense of the main gate stronger.
In this way enemy had to pass through 2 gates.

Many such forts also double as Sarai/inns as rooms would be built into the walls for lodgings.

Most forts would be built on mounds to give them an advantage in height, albeit a small one.
This would also mean that they had retaining walls with higher ground inside than outside. Even if the wall would be knocked down, there would still be earth behind it.

The fort could be supplemented by more walls inside or outside the wall or even a moat.

In many cases this design is tweaked.
For e.g Khangarh is a hexagon than a square and Lahore is an approximate quadrangle.

Some square forts outside Pakistan:
Bhatinda, Punjab India
Lalbagh, Bangladesh
Shanewar Wada, Pune India
Kishingarh, Rajasthan India