Sparki has a hole in its center to hold markers. With a marker in the center, Sparki can draw out shapes by moving with its wheels.
Ideally, when the marker is inserted into the hole, it should hit the paper without being able to be moved much side to side. If the marker is too small for the hole, it will drift from side to side when Sparki moves from one side to another.

How It Works
Certain markers work better than others. We offer markers in the Sparki Materials Pack, and also recommend Expo Vis-a-Vis markers, which are commonly found wherever whiteboard markers are sold.