>>7635012
>>7635040
Boxes made out of physical stuff

Doesn't top my favorite, which is the cross sectional exercise, but there is something to be gained from being restricted to a box shape.
It's very effective at unlocking the sculptor mindset, and I think it works the best with organic textures. The only downside is that it's not a "fast" exercise, but it's still worthwhile. Next time I do this exercise I would probably attempt aluminum foil, another sponge, fur and crumply fabric textures like lace or ruffle.