Tangrams

tangramcrafts

I wanted to make tangrams for my school, and I discovered that lined 3”x5” index cards are perfect for making tangrams! This is because the distance from the top line to the bottom line is exactly 2.5” and the lines are 1/4” apart, so the middle line is marked.

To make tangrams out of an index card:
0. You could cut off the top and bottom outside the lines if you want, to give yourself straightedges and not get confused. Or you can do that at the end, and use another index card for a straightedge and perpendicular.
1. Fold the index card in half, to make two squares, and trace the resulting line. Draw the diagonal in one square to make the two big triangles. Make sure to check that the two diagonals meet at the center card-line, thus:

It's hard to see, but the topmost index card is showing the diagonal on the bottom, which meets the pencilled line in the middle.

It's hard to see, but the topmost index card is showing the diagonal on the bottom, which meets the pencilled line in the middle.


2. Start the diagonals in the other square, but only to the center point of that square (which, again, you can find using the index card’s middle line). Now you have the medium-size triangle.

3. Using the other index card to make a perpendicular line, draw a vertical line halfway up in the middle of the second square. Mark the same line at the top. Now you should have the square and one small triangle.

4. Draw the last diagonal from the side of the card to the midpoint of the top line, so that you have the parallelogram and the other small triangle.

I am in the Madrid Café at 45th and Sansom, Philadelphia.  The owner was happy to try tangrams.

I am in the Madrid Café at 45th and Sansom, Philadelphia. The owner was happy to try tangrams.

I also discovered a tangram alphabet, whence the title picture.

Finally, I made my own “paradox.” I’m sure this has been done and googling will reveal it; nevertheless, I invented it myself. 🙂 Having gone back to tangrams with a much more mathematically trained mind than I had as a child, I always consider the lengths of sides and parallel positions and so on, so it’s much easier to solve tangrams and to puzzle out things like that.

Wait, one of the squares has a hole in it...

Wait, one of the squares has a hole in it...