I'll show you how to make a winged heart valentine whose wings actually flap when you give it a nudge.
Some wood (great way to use up some scrap pine)
Saw (something with a thin blade that can cut curves)
I made mine at http://techshop.ws
Step 1: Select and Prepare Your Lumber
You're going to be gluing several layers of wood together, so once you've selected your lumber, make sure the surfaces are planed nice and flat so they'll stack and glue together seamlessly. We're going to have three different thicknesses of wood:
1. Two cover pieces, front and back. These should be pretty thin, but not so thin that they'll snap. I ended up around a 1/4 of an inch each. To save on material, I split a 2x6 down the middle using a bandsaw to give me two thinnish sheets, then planed them down a little further.
2. One core piece, to which we will attach the front and back. Mine was about 3/4 of an inch. Looking back it probably would have been possible to get the covers and cores cut from the same 2x6, which would have made lining things up just a little easier.
3. Two wings, which will pivot on a hinge slung between the front and back covers. These need to be slightly thinner than the core piece, whatever measurement you used there. I cut mine out of some scrap 1x4 that I planed down to be slightly thinner than the core heart piece.
Step 2: Draw Your Shapes, Transfer Them to Your Lumber and Cut Out the Outlines.
The wing can be free-hand drawn, or if you lack artistic skill (I feel your pain), grab some clipart from the net and print it out in an appropriate size. When designing the wings, make sure to include material that will extend into the side of the heart and act as a hinge.
Once you've got paper templates cut out, trace them onto your wood: Two wings, three hearts.
Using a band saw, scroll saw, jig saw, coping saw or whatever else you have at hand, cut out your shapes. I prefer to leave just a bit of extra material around the outside so I can sand down any imperfections without compromising the shape of my piece.
Step 3: Cut Out Slots for Each Wing
Using your paper templates, mark the pivot point on the wing and on both sides of the heart, then transfer these points to both wooden wings and all three heart shapes. Always use the center-line of your heart to orient the template.
Position the wing pieces over the core so that the pivot points of the wings line up with the points on the core. Move both wings to their highest 'flap' position and trace where they overlap on the core. Move both wings to their lowest 'flap' position and trace where they overlap on the core. Now, cut out the shapes you've drawn on the core. Cut off a little bit extra to make sure the wing has enough clearance to turn without rubbing at any point.
At this point we need to consider the weight of the heart vs the weight of the wings. If we imagine the left half of the heart and its associated wing as a different object than the right half of the heart and its associated wing, we want the center of gravity of each of those two objects to be somewhat outside the heart. We can either make really heavy wings by gluing pennies to their backs, or we can hollow out the middle of the heart. I voted for hollowing, so at this point I drilled a couple holes though the core and cut out a significant portion of its center with a jig saw. I actually did that further on in my build, but wished I had done it at this point since the staples used in the next step get in the way of making cuts once they're sticking out of the wood.
Step 4: Get Your Hearts Aligned
I prefer to stack them all and run a belt sander around the edge, but we need to keep the pieces from sliding around as we work. Get a staple gun and a thin strip of nearly flat scrap of wood to use as a spacer. Lay the scrap on top of the core and fire a staple so that it straddles the scrap. Slide the scrap out from underneath the staple, leaving a loop sticking up out of the core, similar to a croquet gate. Staple two staples into the heart in this fashion, one on each side. Then, using wire snips, cut off the top bar of each staple. This will leave four small prongs sticking up out of the core heart piece. Gently lay one of your cover hearts on top of the core, line it up as best as possible (aligning the center is the most important aspect here) and then push it down firmly so the prongs sticking out of the core imbed themselves into the cover. This will make the pieces resist sideways pressure, but still let you easily remove the cover. Repeat this process on the other side of the core for the second cover piece.
Now, with all three heart pieces stacked, run a belt sander around the edge until all three of the edges are flush all the way around. The top of the heart can be tricky to get, and a smaller sander or sanding block may need to be used to get into the corner.
In the spirit of 'measure twice cut once', when you are satisfied that all three hearts have the same outline, mark an inside surface of each piece so you can tell what order they stack in. Flipping a piece during any of the following steps will cause their outline to be misaligned.
Step 5: Make the Hinges
Take the pins or nails that you have selected and cut them to the appropriate length (be sure to at least cut off the end of the nail with the head on it) so that they will extend from half-way through the front cover, pass through the wing, and end half-way through the back cover, leaving no visible trace of them once the piece is assembled.
Step 6: Glue It Up and Paint It.
Once the glue is dry, scrape off any glue that may have pushed out of the seams around the edges.
Using a paint of your choice, add some color to your creation. I used some acrylic that I had lying around, and two coats seemed to give fair coverage they may show through unless you really layer on the paint. Be very careful when painting around the hinges. The acrylic I used added a LOT of friction if any got on the inside of the cover at the wing slot, and I had to sand it out by sliding a sheet of sandpaper between the cover and the wing. It was pretty awkward, and I recommend avoiding it if you can.
As a final touch I outlined the wings in black sharpie just to give them a little bit of contrast.
If your calligraphy is up to snuff, you might as well paint a message of adoration on the heart as well.
Step 7: Suspend It
You'll get the smoothest flapping motion if the fishing line extends straight up from each wing when hung instead of angling together towards a single point above the middle of the heart. You can use a length of wood whose length has been cut to be the distance measured from nail to nail, and attach the fishing line to each end of that piece of wood. I hung mine over the edge of my mantle and counter-weighted it with a hefty paperweight (not pictured).
You'll notice in the video that the wing on the right doesn't move quite as freely as the one on the left. There's a tiny piece of the wing that rubs ever so slightly against the surface of the back cover, but it's enough to throw off the motion. Triple check all your clearances before you glue!