With my best friend's birthday looming and an ever-restrictive poverty class budget being enforced by my loving and beautiful wife, I faced a bit of a problem. He and I had been joking for months about building a prop from Portal 2 (mostly hoping for a Space Core), but my budget and time just weren't there.

Presenting the learning experience that followed: The $30 PotatOS clock.

I knew I'd never be able to make this completely accurate to the game model with my limited skillset and materials, so I set out instead to find parts that could approximate the general idea.

Key to this project were:

Foam and tools to shape it (I used a fine floral styrofoam)
16 gauge primary wire
A small mailbox reflector (orange, obviously)
A PVC nut and washer from the plumbing section at Walmart
A clock movement
Additional scrap foam
Gator clips
Nails
Staples
Glue dots

Step 1: Pattern Time!

Take a marker and get a feel for the shape of your potato. Then start carving!

Step 2: Figuring Things Out

Here, I started assembling the eye/brain portion and figuring out how it would translate into a clock. Eventually I realized that I would need to carve an additional window into the "potato" to help house the clock movement.

Step 3: Details, Details.

Finish assembling your clock movement, and get ready to get dirty.

Painting foam is a chore, and I considered multiple ways to go about it (such as plaster bandage coating, papier mache, etc), but in the end I found a nice protective coating that could be layered onto foam shapes and dried overnight.

Collecting two shades of brown, sponge brushes, and an eager three year old, I set about painting the potato (which had been whittled down tremendously to fit in the final display).

I used a tan acrylic base, and sponged in darker brown to make the dirt and eyes.