Pictures of your work are welcome!
SAFETY ADVICE: This instructable use sharp tools. Be careful about it. If you are not sure how to use them, don't continue. For kids, it is MANDATORY adult supervision and help.
Step 1: Tools and Materials
1 - Sheet of cardstock (white or coloured).
2 - Paintings.
3 - Magnet add (those flexibles and thin).
4 - Pencil and rule.
5 - Cutter and cutting mat.
The painting technique I'm going to use is colour markers with water (I don't know if there is another name for that), but you can use your preferred one.
Step 2: Cutting
The result must look as the second picture. Once folded, review the borders and cut again to make them equal if necessary.
Step 3: Painting
Don't worry about if paper is bending, let it dry up putting on some heavy book for a couple of hours (protect the books from water using tissue or plastic).
After that, repaint the drawing with thin lines to emphasize it.
Step 4: Applying the Magnet
Put them together to be sure one attracks each other, and apply glue at external sides. Stick them to one part of the card, and then close it.
Finally, ensure the both magnet match and... you are ready to surprise your family and friends!!!