I used a dead laptop, a pizza box, and a cereal box to make my own abacus, the original computer!

Step 1: Materials: Dead Laptop, pizza box, cereal box, tools

Step 2: Disassemble the laptop
Step 3: Remove the keys from keyboard
Step 4: Layout and make front panel for abacus
Step 5: Align keys, tape, and start calculating

Step 1: Materials

You will need:
Dead Laptop (found in trash)
Pizza box cardboard or box cardboard
Cereal box or poster board
Tape (Duct Tape always works)

Tools I used:
Jeweler's screwdrivers (to disassemble laptop)
Flathead screwdriver
Scissors
Knife
Pencil
Ruler

Step 2: Disassemble Laptop

After removing all the screws in the laptop and using a flathead screwdriver as a pry bar, I removed the keyboard from the laptop. Note: This laptop was full of sand; it's circuits were underwater.

Step 3: Remove the Keys

Using a screwdriver and a lot of patience, I removed all the keys from the keyboard.

Step 4: Layout and Make Front Panel

Using a key as a measure, I laid out the spacing for the front panel of the abacus. Notice that my ruler is part of the cereal box. I then used my knife to cut the pattern for the front panel out of the cereal box cardboard.

Step 5: Align Keys, Tape and Start Computing

I laid all the keys out in a design for a Roman abacus, with 70 keys in 10 columns with two rows.
After aligning the keys on top of a piece of pizza box cardboard, line up the front panel cardboard on top.
Put tape around the edges, and you are ready to start calculating.

Note:
You can untape the front panel at any time, and rearrange the keys in any order. If you note the position of the keys numerically, you have an instant simple cipher coder/decoder.

For example, in my abacus, 'A' is in the 2 position. 'J' is in the 23rd position.