How are the Koopa Trace Walking and Picture Match challenges graded?
I would guess that:
- Trace-Walking is graded on the perimeter of the outline the straightness/circularity of the edges, and the position of the corners (if any).
- Picture Match is graded on the accuracy of each piece's position and rotation.
The grading would be primarily based on deviation. A perfect score would be an exact recreation. A 100 is still awarded for very minor deviations from the target. As the amount of deviation from the target increases, the score goes down, probably linearly.
(disclaimer: this is mostly instinct and logic, with not much hard proof)