Category: Unplugged Project

Secret Codes: The Cardan Grille (“Messages” Unplugged Project)

By , January 10, 2011 2:39 pm

My two oldest children are really into secret codes at the moment and when I asked them for suggestions for this month’s Unplugged Project theme, my 8 year-old son immediately said “Messages! We could make codes!”

So here is our first code, a version of the famous code known as the Cardan Grille.  For this code, a special template is used to encode and decode a message. Here’s how we made ours:

You’ll need paper (graph paper makes it much easier), a sharp pencil, scissors, a ruler, and a box cutter or razor blade.

First mark out evenly spaced boxes on your graph paper.  You will be cutting some of these into square openings, so you’ll have to leave some blank space around each box.  (Our boxes were two graph squares wide and two squares tall with one blank square between rows.)

First we marked off rows of squares then we drew the grid using the ruler.

Next we laminated our paper.  If you don’t have a laminator, you might want to paste it to some stiff cardboard or posterboard just to make it tougher.  If the grid gets lost or destroyed, no one can crack the code and you will be fired as a secret agent!

I used a box cutter to cut random squares out of the grid.  I put an old wooden clipboard underneath in order to avoid damaging the desk.  You could use pointy scissors for this step, but a razor-type blade makes the job much easier. (Obviously, an adult should do this step.)

The finished template (with my “helpers” in the background):

Now you are ready to encode.  Place the template over a fresh sheet of paper.  Mark around the corners with a pen to make it easier for the decoding person to line it up.  Write your message (one letter goes in each square).

Remove the template and fill in all the open squares with random letters.  Can you figure out what this says?

Here is the solution:

(“The girls are hiding the treehouse.” – OK, so it was supposed to say “The girls are hiding in the treehouse but we forgot the “in.” But coded messages are supposed to be brief, right?)


  • You can make your template as big or as small as you like.
  • For ease of communication between spies, you really ought to make a duplicate template so both sender and recipient have their own.  Just place the first template over a new piece of paper, trace the locations of the squares, laminate, and cut out.
  • I numbered the corners of the template 1 – 8 because you could use both sides and all four orientations to create different messages, or even one long one.
  • Traditionally, the template was placed over an ordinary letter (see the example here) but it can be very challenging to come up with a natural sounding message built around the coded text.  I gave it a try though and it was a fun mental exercise:

(“Arrival at six PM.”)

Messages – Monthly Unplugged Project

By , January 4, 2011 6:38 pm

As I mentioned in my previous post, I am back on track with our Monthly Unplugged Projects in 2011!

The theme for January’s Unplugged Project is:


Anyone can join in the Unplugged Project.  Be creative!  Any connection to the theme is fine.  I try to pick a very general theme each time so that each project and interpretation will be unique.

If you have an interpretation of the theme messages to share, please review the information on how to join us here.  You have until February 1st to post your link.

(NOTE:  Please only link to “messages”-related projects. I will have to remove unrelated links, no matter how nice your website.  A link to Unplug Your Kids in your project post would be greatly appreciated too!  :-)  )

Giving Thanks – Monthly Unplugged Project

By , November 20, 2010 12:42 pm

I have been so busy sorting and de-junking my house, that I have had little time to blog and my Monthly Unplugged Project has fallen a bit by the wayside.

Even though we are already halfway through November, here is a theme that we can perhaps do before the end of November since, in the United States, the Thanksgiving Holiday is coming up next week and many of us are already thinking about how to give thanks.

How do you give thanks? Do you have projects, artwork, crafts that fit the theme of giving thanks?

Join in and have fun! If you have never joined us before, please consider it. You can read more about how it works here.

I’ll start it off with a link to a “thankful” project that we invented and enjoyed.

(Please only link to “giving thanks”-related projects. I will have to remove unrelated links, no matter how nice your website.)


Pretty – Monthly Unplugged Project

By , August 3, 2010 6:40 pm

Again, I am LATE!  The problem with trying to be unplugged is, well, you are often unplugged.  I guess that is a good thing.

The theme for this month’s Unplugged Project is the very open-ended concept of:


Have fun and be creative!  If you have never joined us before, please consider it.  You can read more about how it works here.

Clam Shell Mobile – “Beach” Unplugged Project

By , August 2, 2010 2:01 pm


As is my pattern these days, I am a day or two late in posting our project for July’s Unplugged Project theme of beach.  Oh well!

I am such a packrat that I have had these clam shells sitting around all summer.  In fact, I am embarrassed to admit that I saved them from a fabulous meal in Upstate New York back in June and brought them all the way home with me!  (I just don’t really trust Arizona seafood.) We soaked them in hot soapy water right away after eating to clean off any grease and smell.

We used a dremel tool to drill a small hole in each one.  You’ll need a good masonry drill or dremel bit for this since, as we discovered, clam shells are quite hard.

Before we began painting, we soaked them again, this time overnight in pure bleach just to get rid of the last lingering slightly clammy smell. We then rinsed them off in cold water and let them dry.

Next we painted the outside of them bright colors. (I think it would also have been a pretty project with them left as-is, but my daughter wanted them to be colorful since this was to hang in her room.)

After the paint dried, we decided to splatter them with gold paint using old toothbrushes.  Fun but a bit messy!

We left the inside natural, but you could paint that too if you want.

After they had dried completely (overnight), we strung a piece of fishing line through each one.  My daughter brought in four sticks from the yard to make the frames for hanging them.

We tied each pair of sticks together in the form of a cross using yarn and then hung one shell off each arm of one of the crosses.  We suspended the second cross below the first using yarn to create a second tier.  We again tied one shell onto each arm and hung our final one much lower from the center.


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