At top, a box labeled “base or parent class” contains the following lines:

   Device
string model
string serialNumber
string status()

Below are two boxes, each labeled “derived or child class” and “inherits model serialNumber and status() from Device class”. The box at left contains the following lines:

   DoorDevice
string status()
void openClose()

The box at right contains the following lines:

   ThermostatDevice
string status()
void setTemp(int t)

Arrows labeled “IS-A” point from both of these boxes up to the parent class box.