Deriving an abstract class from concrete class

Let's say we have a concrete class Apple. (Apple objects can be instantiated.) Now, someone comes and derives an abstract class Peach from Apple. It's abstract because it introduces a new pure virtual function. The user of Peach is now forced to derive from it and define this new function. Is this a common pattern? Is this correct to do?

Sample:

class Apple
{
public:
    virtual void MakePie();
    // more stuff here
};


class Peach : public Apple
{
public:
    virtual void MakeDeliciousDesserts() = 0;
    // more stuff here
};

Now let's say we have a concrete class Berry. Someone derives an abstract class Tomato from Berry. It's abstract because it overwrites one of Berry's virtual functions, and makes it pure virtual. The user of Tomato has to re-implement the function previously defined in Berry. Is this a common pattern? Is this correct to do?

Sample:

class Berry
{
public:
    virtual void EatYummyPie();
    // more stuff here
};


class Tomato : public Berry
{
public:
    virtual void EatYummyPie() = 0;
    // more stuff here
};

Note: The names are contrived and do not reflect any actual code (hopefully). No fruits have been harmed in the writing of this question.