I am very proud to present the finished Window Real5x5x5. I've been working on putting a 3x3x3 inside a 5x5x5 off and on since November 2006. This is my third such design and my second which has been turned into a functional puzzle. The notion of a 3x3x3 inside a 5x5x5 was first published in a Cubism For Fun (CFF) article called Hidden Cubes by Tony Fisher in July 1989. The first simulator which would let you play with and solve this puzzle was the program CubixPlayer2 made by Per Kristen Fredlund and released in April 2004. To my knowledge this is the second physical/functional and stickered version of this puzzle. The stickering was completed July 31, 2014.
This is a Multi-5x5x5. Multi means that all 5x5x5 or 125 cubies are present in this puzzle and solvable. The 1x1x1 at the center (or core) isn't stickered but its position and orientation can be deduced at all times from knowledge of the 3x3x3 and 5x5x5 face centers. This is NOT a Super 5x5x5 unless super stickers are used. With normal stickers (like the ones in the photos), the orientation of the 3x3x3 and 5x5x5 face centers can not be determined and there are 4 identical copies of each of the x-centers and t-centers. Note most 5x5x5's only allow you to solve 98 of the 125 cubies.
The finished puzzle has an 80 mm edge length and it weighs in at 172 grams. This one was printed in White Strong & Flexible (the default material) and dyed black using Rit dye.
Stickers for this puzzle may be purchased here.
In addition to the 132 parts you will get from Shapeways you will also need 6 M3 10mm Screws. These screws should be 10mm long but other then that any 10mm M3 screw should work. These are the screws that I am using.
You can read more about this puzzle in the Twisty Puzzle forums here.