I printed this model of a Death Trooper Helmet (from Star Wars Rogue One) at 2 perimeter walls and 10% infill. While printing the thin sections, the infill pattern can't be discerned - it's just an inner line here and there inside the thin wall.
However, after putting all the pieces together I could see the patterns the infill structure made. I took some photos after putting a light bulb inside to highlight things.
It's pretty cool that even though the pieces were printed separately, some of the infill pattern geometry nevertheless appears to line up between the pieces. Neat!