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.