The third obstruction is actually quite a poor excuse for an obstruction

3. Because Leth failed to complete task 2 perfectly, Trier punishes him, telling him to either remake the film in any way he chooses, or else to repeat it again with obstruction 2 in Bombay. Leth chooses the first option and remakes the film in Brussels, using split-screen effects.

So lets just skip to the 4th

4. Leth must remake the film as a cartoon. He does so with the aid of Bob Sabiston, a specialist in rotoscoping, who creates animated versions of shots from the previous films. As such the final product is technically an animation but not a cartoon. Nevertheless, Trier considers the task to be completed successfully

This time a single formal obstruction however I would argue that this obstruction is perhaps more severe than the previous formal constraints. Creating a cartoon or animation pushes Leth to rethink the film in a very different mindset, opening up new possibilities you can view the piece here > https://www.youtube.com/watch?v=Z8fnntjKmrA

The result is a film that is quite reflexive of itself and Leth’s previous obstructions. The animation gives a fluid quality to the visuals and Leth utilises its own text heavily depicting it with various typographies on the screen.

I think the use of type is one of the most interesting changes because it could have been accomplished without the rotorscope animation. Leth could have added some similar text effects to any of the other obstructions but somehow decided to add it to this one instead, perhaps signalling that this formal challenge led Leth to a find solution that was already present and underlying in his other obstructions.