These are two vases I made using this Printable Filament method. In both cases I printed 30 grams at .2mm layer height.
The first one is Inland PLA Peak Green and Inland PLA+ Blue. I started with 5 layers of green and finished with 2 layers of blue.
The second on is Inland Natural (uncolored) PLA and Inland PLA+ Blue. This one was 4 layers of natural and 3 layers of blue.
Original vase model here: https://www.thingiverse.com/thing:2795194
My take on this whole experience:
It has potential to be a cool new tool in artistic 3D printer's arsenal. But there's a lot of variables to experiment with. It's not as simple as picking two filaments and slapping them together - results probably won't be so good as I've demonstrated above with my work (the green/blue combined to a color that's not particularly attractive, although it is interesting in effect, and the natural/blue the effect is barely noticeable although the color is not great).
For a party trick to show to your non-3D-printing friends, a simple translucent PETG probably has more wow factor.
And it takes a simple 2 hour vase mode print and turns it into an all day affair - taking 4 or 5 hours to prepare the filament just to print the vase.
I might experiment with it more in the future, but as it is neither of these are anything I'd be proud to give as a gift or anything.
I will say from a technical standpoint, it's pretty amazing that it works in the first place.
Inland PLA and PLA+