The Inventor Writer can write and draw custom texts and drawings. I tried out 5 different drawings and defined all capital letters of the alphabet. As always, instructions are provided in ENGLISH and GERMAN language on rebrickable.com.
The provided code (python) is documented in detail and can be amended for custom changes of the model.
Besides the set 51515 Mindstorms Robot Inventor, only a pen and a household rubber band is needed. It also works without the rubber band but will not reach the desired accuracy, as the rubber band is supposed to eliminate the gear play.

More Details on the page about the book The Mindstorms Robot Inventor Expert