The program initiates by telling the user the functions of the keys A-F on the keyboard, whereafter the pen is moved towards negative values of X and Y until the user states that the pen is at origin (X=0, Y=0), by pressing the ``YES'' key.
| Key | Function |
| A | ``Reset'', redefines the origin |
| B | ``Cancel'', aborts input |
| C | ``Help'', shows key usage |
| D | ``Yes'', answers question |
| E | ``No'', answers question |
| F | ``Quit'', ends the program |
Table: Function keys.
Next step is to show the actual position (in this case (0,0)). After that, the program is ready for input. The user enters the coordinates (in integer mm), to get the question whether the pen should be lowered or raised during the next movement cycle. When the coordinates are achieved, the position is shown again on the display, and the program is ready for new input.