Years ago, I found a wonderful paper piggy bank made out of paper. It was a penguin. I immediately download it, printed it, and set to work deciphering the instructions--they were in Japanese. Fortunately the pictures were great.
My students loved the fact that when you fed him a coin, he flapped his wings. Students were forever asking if they could have him. I always printed them their own copy along with the non-English instructions. A few of them were able to overcome all the challenges and make their own.
After making several penguins, I decided it was time to try creating my own moving bank. My artistic skills have never been great so I kept it as simple as I could. I knew I was going to make it many times so I drew it on the computer. The program that I am most comfortable with does straight better than curves--hence the lack of curves.
In my design, I tried to fix the problems that the original penguin had. Japanese coins seem to be smaller than a U.S. quarter--the coin slot needed to be bigger. The penguin's coin slot was not reinforced and would occasionally tear. Most importantly, the original had no coin removal mechanism. To get the coins out, you had to shake it upside down and try to slide them out through the gap between the head and the back of the body. After a while, he always tore. A decapitated penguin is never a good thing.
It took several tries but I ended up with a working piggy bank. I kept the rejected trials for a few years to show my students that sometimes things take several attempts. I think of it as the mathematical equivalent of proof reading and re-writing in an English class.
It only took 3 hours but I finally embedded my first video!
Sorry. All the stress of trying to get the video right and I forgot to attach the PDF of the pieces. I have fixed the problem. See step 2.
Step 1: Materials:
Card stock--3 sheets
Pens, markers, etc.
Step 2: Printing and Cutting
Card stock is important. You can find it in office supply stores and in most craft stores. Check the scrapbooking section. I have used patterned scrapbooking paper but usually have to cut it down to 8 1/2 by 11 to fit it in my printer.
Cut out each piece carefully on the solid lines. The coin slot needs to be cut with a craft knife. The tummy hole is for easy coin removal. Be careful not to tear this space. The arm holes have a little flap that is cut on only 3 sides--also cut with the craft knife.
Score on the fold lines. I keep an empty ball point pen for this. A ruler helps. I have recently started using a credit card to aide in folding. Line up the card with the line. Press on the edge from the back side to crease the paper.
Pre-folding the flaps at the arm holes is very important. Fold them back and forth several times each. These need to be very loose--otherwise the arms will not move.
Step 3: Glue
Patience is necessary at this stage. You have to let pieces dry properly or you will have a disaster on your hands.
Use the smallest amounts of glue possible. A little goes a long way and will dry faster. Glue stick will not work. It is not a strong enough adhesive. After aligning the pieces, hold the pieces together while counting slowly to ten. This will give them a chance to adhere.
My glue is in a gallon jug so I use an empty pill bottle and apply it with an old paint brush. The brush helps to apply the glue evenly. I use the handle of the brush to reach inside and hold pieces while they dry.
Start at the top of the head. Overlap the 2 coin slots. Next, attach the front at the top of the head. After this has dried, you will be working your way down, glueing the face, then the body.
Step 4: The Arms
The arms are very important since the exciting part is to see them move every time you feed the dragon.
It is a little difficult to explain in words how this mechanism works so I recommend checking out the pictures. First you need to make the inner part. You need to glue the weird curved piece to the rectangular piece with the 2 marks on it. Line up the tabs with the marks. The marks are slanted so that the paper does not rub up against the body of the bank when it is used.
After adding the mechanism to the inside of the arm flaps and waiting for it to dry, check to be sure it moves easily. One mechanism gets glued to each arm flap on the inside of the bank. The rectangular piece should be pointing upward. When the coin lands on it, the rectangle gets forced down by the weight and the arm flips up.
Attach the arms to the outside of the arm flaps. If any excess glue seeps out, wipe it off while you can so the arms will move freely.
Step 5: Bottom and Back
It is important to make sure that the bottom piece is secure since coins are heavy. The front flap has to tuck under the tummy to hold the coins inside.
The spikes on the back are purely decorative.
Step 6: Legs
The legs serve the purpose of adding stability to the bank.
Each leg is a separate closed box and when they are attached, they prevent the bank from falling sideways.
At this point the construction of the bank is finished. Time to decorate. I like to use wiggly eyes and a little bit of marker. One time I decorated it with nail polish on the tips of the nails (fingers and toes) and the tips of the spikes on his back.