It's been a long time. How have you been?
After weeks and months of free time, let this Instructable accompany you back into Real Life. Wipe the dust from your desk chair and find out that it does absolutely not fit to the clean and sober atmosphere you want to dispense with your homework. What could be more engaging and mind-stimulating than a multi-purpose Companion Sitting Cube?

Ready for the release of Portal 2, here is the Instructable to sew and glue your own Companion Cube as a desk stool, gaming taboret or side table.

This is an entry for the Back to School-Contest. If you like it and if you grant me a super cool Eee-Netbook, please vote and comment. Thanks!

Step 1: The Material

You need:

A (hard) sitting cube - This can be the ugliest cube you have ever seen, lilac with Minnie Mouse appliqués, it doesn't matter. Used ones do also work. The core should be hard, e.g. styrofoam, no air- or bean-filled cubes. 10$

Artificial leather - Normally this is sold per meter, with a width of about 1,20 - 1,40m. You will need one meter of grey and one meter of champagne. 2 x 7$

Black twine - 1 - 2 of those twine stars. Yarn should also do it, but doesn't look that nice. 2$

Pink tinting paint - Or red and white mixed. You need as few as you can get. 2$

Styrofoam plate(s) - About 1 - 2cm thick. 2$

and some stuff that every one should have, like
glue, crepe tape, cardboard, staplers (that normal one and that strong one), scissors, sewing stuff.

All in all, this costs about 30$.

Step 2: Preparation

On the second picture below, you see that Chell doesn't feel comfortable at all when sitting on the cube (Well, she is acting unstressed, but actually she is clenching her teeth). The high edges cause a hollow back, which will give her inevitable backaches.

This is why I idealized the model of the cube a bit, you can see that the edges aren't as high as in the original game.

Print this pattern in the right size on thick paper, so that the line on the right measures half of one side of the cube. When you print it with 100% size, the line is 20cm long (for a cube of 15,7").

Cut out the grey areas (Don't mind the dark grey areas yet, they belong together) and transfer their shapes with a pen on the backside of the champagne-colored leather in the right number. You don't have to transfer the heart, only the circle.
Important! Leave a border of 2 cm for every piece.

On the second picture, you see how the shapes have to be cut out. This needs no sketching first, just cut them out roughly.

When you are done with the patterns, you can cut out the 2 dark grey areas and use them as a sample for the styrofoam plate pieces (Again only the circle, not the heart). You still need the triangle 20 times and the circle 5 times. You can lay the styrofoam plates on each other to cut it out with a carpet cutter.

Image: http://fc08.deviantart.net/fs46/f/2009/225/d/2/Chell_by_Kibaruto.jpg

Step 3: Covering the Cube

Now it is time to cover the naked cube with the grey leather.
Lay your cube on the backside of your grey leather and draw its shape 5 times with a pen and make it a bit longer on one side 4 times. Leave a gap of 5 - 10cm between the rectangles.

When you cut them out, be sure to leave a border of at least 2cm on every side.
The square will be the top part of the cube, so start with sewing the other 4 pieces to it and after 4 lines, you have a cross. Then sew the 4 other edges and you have the inverted cube.
This is how you sew:
Hold the pieces together so that leather touches leather and the pen lines are on the outer side and in line. Fix the parts with the stapler on the border and sew both pieces together, either with the sewing machine (which I unfortunately can't handle) or per hand. The picture shows how it should be sewed.
Tip: The twine you will need is always about 3 times as long as the line it sews.
When you are done, cut the border with the staples away.

At the end, you should have an inverted cube with 5 sides that you can turn inside-out now. Pull it over your sitting cube and fix it with the strong stapler on the bottom.

Step 4: Adding the Color

Mark the center of each edge and stick crepe tape left and right beside the center line, which should be about 1cm thick (0,4").
Then add the pink color between the tape stripes as seen on the picture (Don't mind that there are already a few edges applied - I thought it would be boring to sew all 20 edge-parts in a row). After a few hours you can remove the tape.

To paint the hearts on the circles, take the template with the cut-out heart and lay it over the 5 leather circles, spotting the pink color carefully with a thick brush.

Step 5: Adding the Edges

Prepare the 20 edge parts as seen on the picture. Fold the flaps inside and sew along the edge, that the (nice) dotted twine-line is on the outside and the (ugly) thick line is on the inside.

Now you need 4 pairs and 4 trios.
I will begin with the trios. Sew them together as you did with the cube-covering - inverted (leather facing leather), fixing with staples, cutting the edge away, turn inside-out.
When you now lay the edge on the edge of the cube, you will notice that it looks kind of creepy, because it lacks of depth.
So take a bit of twine and sew the 3 parts a bit under the edges with 3 single knots together (Hard to describe, just take a look at the picture). This avoids that the edges are laying flat on the cube.

After you have finished the edge, take 3 styrofoam triangles and fix them on one of the 4 top edges with double-sided tape or glue. They will fill the edge and make them more fluffy.
Now you need to put a generous portion of glue on the inner side of the trio along the twine-line and fix it on the cube. Not all glues are suitable for holding leather together.

Same procedure with the pairs of edge-triangles. These go to the 4 bottom edges of the cube. On the bottom plate, they can be fixed with the strong stapler (see picture).

Now you can prepare the 12 center parts. First you have to sew the flaps on the inside, all around the shape, and then glue it to the right place. It is probably no surprise that the 4 halves go to the bottom edges of the cube.

Step 6: Adding the Love

I can't love a Companion without a heart. The cube got even 6 of it (The sitting cube only 5, but you can draw a quick sketch on the bottom if you can't resign the 6th heart).

You need to take the styrofoam circles and glue them in the middle of the non-leather-side of the leather-circles. Fold the flaps on the inside and fix them with tape or you will get a frustration attack while sewing. Don't fold them along the styrofoam - fold them along the pen line, so that the leather circle is still a bit bigger than the styrofoam circle.
Then sew along the edge - you should have left enough space between styrofoam and leather-circle-edge that you don't need to sew through the styrofoam.
Tip: You will need twine of about 6 times the diameter.

When you are done, fix the circles to the middle of the cube's faces with glue along the sewing line.

Step 7: Receive Cake

Congratulations, your Companion Cube is done and ready for assisting you.
The field of application is mind-blowing, but I recommend to use it for recreation purposes like playing genius video games, creating the effect of "Wow, I am just sitting on this object which I carry around right now in this game".

I think no one will raise an objection if you throw away that nasty old desk chair and replace it through this unique piece of fine leather art, letting the Zen in your room directly flow into your brain.

Thanks for reading and happy sitting!

(Here is still a picture to come of me sitting on the cube to show size relations, but my Portal 2-shirt is in the laundry ;))