grid property

The @override late final List<List<int>> grid; is declaring a late final variable grid of type List<List<int>>. The @override annotation indicates that this variable is overriding a property from a superclass or implementing an interface. In this case, it is overriding the grid property from the BasicShape interface. The late keyword indicates that the variable will be initialized at a later point before it is accessed. The final keyword indicates that the variable cannot be reassigned once it is initialized.