The students used just a sharpie pen, no pencil! That way the 3rd graders can get used to making mistakes and being okay with it.
The sky's the limit when it comes to what their robot can look like. 2 heads, 6 arms, flying above a city, riding in a car, you name it - they can draw it.
The only thing that their robot needs to have is cross-hatching. Cross-hatching is a shading technique, in which one set of lines crosses over (overlaps) another set to show value.