Step 1: Obtain high-contrast templates
Print the file, and cut out the images. Warning: this will use a lot of black ink.
Step 2: Prepare wire hangers
Step 3: Tape the hanger legs
Step 4: Twist and tape the top of each hanger
Step 5: Combine the hangers to form the mobile structure
I also straightened out the hook parts, twisted them together and taped them up.
Step 6: Making the dangling objects
From here, you can poke a hole in them and hang them, or you can add some more of the cutouts to the top in the shape of a "T" like I did.
Step 7: ...and you're done!
The final, final step is to suspend it over your baby. You can do this in many ways. We re-formed the top back into the shape of a hook and attached it to an old floor lamp with a swing arm using some nylon webbing.
your homemade baby mobile is done...enjoy!