Using a few boxes from the recycle bin and a couple cans of spray paint, you can create these beauties!

Since cardboard is usually comprised of three layers, we can cut away to show depth and negative space.

A simple Google search of "silhouette artwork" will yield many inspiring pictures for your delight.

While this works best for large, simple images, you are only limited by your space and patience!

Step 1: Starting Out

I asked the local fast-food joint (Culver's) for any boxes they had, and they filled my car with french fry boxes.

It only took a couple pints of delicious custard to bribe them...

If that doesn't work out, looting the dumpster may be an option, albeit an unpleasant one.

All large boxes like these have a seam that I prefer to cut along, to easier cut into squares.

These boxes were more rectangular, so I'll have to cut them to get them exactly square.

I used a carpenter square with a utility blade to get them exactly 12"X12", canvas style.

I also used:

Cork-backed 18" ruler
Xacto blade
Cut resistant gloves
Tweezers (serves two purposes..)
Marker/pen/pencil
Weldbond/PVA/wood glue (adhesive)

Step 2: Testing the Fixatives

I tested four types of glue on cardboard scraps, taking up roughly the same area of 3" diameter

I gave them an hour to dry with light pressure on the bond by way of a scrap of 2X4

Strength was tested by me pulling them apart (I know.. really accurate...)

Clockwise from upper-left:

Wood Glue in squeeze bottle: works well, takes a while to dry, applying pressure increases grip
Weldbond Glue: my prefered type of craft glue, works well in this application
Rubber Cement: peelable glue, would not recommend for strength
PVA Glue: acid-free, generally used in bookbinding, prevents "bleeding" of ink

Based on the results from my little test, here's the adhesive strength from greatest to least

Weldbond glue/Wood glue -- Both worked really well, couldn't tell the difference without a laboratory
PVA -- Absorbed fast into the cardboard, but holded up quite well
Rubber Cement -- barely held, would not recommend for something so thick

Step 3: Layering and Preparing

A single layer of cardboard is kinda flimsy, so i glue two together in a criss-cross style to strengthen it and add depth

Peeling is liable to happen around the edges if they are not properly glued, which is why i apply most of the pressure around the edges with extra glue.

A couple of holes on the back with a carpenter's square gives easy mounting with two level nails 10" apart.

Since this mounting is so simple, you can create a variety of masterpieces to place over your mantel.

Step 4: Trial by Experimentation

Watching Karate Kid recently inspired this Rising Sun type silhouette. Not bad considering this was all from memory and eyeballing the measurements. Ehhh, I just like experimenting and trying new processes.

I used an exacto knife to inscribe the design, then the first layer was peeled away with the back end of a tweezers

A little fluff was left over, and the tweezers was perfect for picking that off (a multitool!).

Although a little time-consuming, this is a perfect activity to do while watching tv!

Step 5: Watch Over This Design..

By layering the cardboard silhouettes, one can create a field of depth to add shadow and effect,

Can you guess what symbol this? Hmm? I'll save the reveal for later...

I eyeballed all the measurements, so I couldn't provide some sort of template, but It's easy to print it off and trace using carbon paper or other media.