A harmonograph is a mechanical apparatus that uses pendulums to create a geometric image.

These can be either very simple (like the one I will show you how to make), or complicated. Google 'harmonograph' to learn more about the more complicated ones.

Step 1: Get Supplies

Supplies

- A large, strong, flat board. You can use a lot of different things for this part. I used a shelf from a bookcase.
-Weights. Get at least 5 pounds. More is better though.
-String
-Paper
-Pencil/pen. A pencil works better because it slides better than a pen.
-Duct tape. Of course.
-A book or other small object with some weight. Just about anything will work for this.
-A coat hanger, or dowel rod. A coat hanger is better. I'll show you why later.

Step 2: Find a Place to Mount the Strings

This step can be hard.

You need to find a place in your house that has something near the height of the ceiling that can support 10 pounds while the weight is swinging. But there have to be 4 places to hold the weight up. These four places should be in a square formation too.

What I did was I went into my basement, lifted up the ceiling boards (Like the cheap ceiling schools have), and mounted the strings from a board that supports the floor above it.

I've heard of people using door frames as the mount. You can try a door frame, but I don't know how strong door frames are. So watch out.

If you can't find a place to mount the strings, you can usually find a place to hammer some nails in.

Once you find a place to mount the strings, find a chair, table, anything like those two things.
Now measure the four strings from the place that you're going to mount them at down to the chair/table's level.

Step 3: Mount the Board

Now, tie your four strings up, and let them hang.

Make sure they're all even!

Now find a way to attach the board to the strings on the four corners of your board.

This is why I recommend using a bookshelf. They usually have something on the ends of the board to mount them in the bookshelf frame.

Make sure it's secure. If it's not secure, duct tape it.

The board should be level now. If it's not, adjust the strings so it is.

Step 4: Make the Pencil/pen Mount

Take a book or something else with some weight, and attach an arm of some sort to it.

You can use a coat hanger or a dowel rod. A coat hanger is better.
Just make sure it reaches about a foot away from the chair/table.

Now tape the pen/pencil to the end of the arm. Or you can wrap the coat hanger around it if that's what you're using.

Step 5: Now Test Out Your Harmonograph!

Put the pencil/pen mount on the table/chair, and set the pencil/pen right on the board so it's barely touching.
This is why the coat hanger is better. You can bend it an place it right on the board.
But if you do use a dowel rod, just use some playing cards or something else to hold the mount up at the right height.

Tape some paper on to the board, and give one of the corners of the board a push. The board should be twisting and swing back and forth.

Now watch your harmonograph form amazing designs