3D printing machines are not uncommon these days, and are probably what a lathe and mill was to many 50 years ago.
So you (or someone else) could print a labyrinth of HIPS and HDPE layer by layer (both of which are available in 1.75mm or 3.0mm spooled filament – although not that common, especially not HDPE, partly as its nearly impossible to get it to bond to anything, and it degrades slightly when extruded – I think)
This would be completely impossible using conventional methods and on a dual extruder machine the HDPE and HIPS could be interwoven without needing to stop and change the filament! I would say probably start with HIPS as it will more easily bond to the build plate and then capture pockets of HDPE in the HIPS and build up layer by layer from there – its as simple as designing the part in 3D and using a software like MatterControl with MatterSlice or Slic3r it will automatically "slice" the 3D part into layers of your chosen thickness and print away automatically.
I wonder if a thin piece could be 3D printed made up of dotted HIPS and HDPE as a sort of bonding medium via suitable chemicals between pieces of pure HDPE and HIPS
I have a large 3D printer but it's a single filament machine and I'm not planning on converting it to a dual material/color any time soon (walking before I can run!)
Here's the sort of quality a novice (that's me!) can achieve. This was Verbatim ABS printed in 0.1mm layers through a "medium" 0.5mm nozzle @230°C on a 80°C borosilicate (Pyrex?) build plate with Elmers Disappearing Purple glue (as ABS doesn't stick to glass!) – All good (clean!) fun and easy to keep SWMBO happy with pretty pussy cats for calibration pieces

And for my next trick: http://www.thingiverse.com/thing:536050

Edited By Russ B on 10/11/2015 14:38:16
Edited By Russ B on 10/11/2015 14:39:31
Edited By Russ B on 10/11/2015 14:41:03