I do not know if the object exists, I know that the pantograph central symmetry where to dilation, but I think it's a beautiful object to illustrate the course of the axial symmetry sixth and to give an application of the properties of the diamond in fifth.
Edit: After two three studies, I realize that not only the object exists, but there are also pantographs for travel, for the similarities and rotations. very clever too.
construction:
On a board, I screwed a rack that will act as rail.
I put two wheels (recovered from an old piece of furniture) that fit the size of the rail and I asked which branch of the same size Meccano.
This gives a diamond. On the other two peaks, I asked two short strips of bent where I felt stuck so they receive the support. It
sellotape two sheets of paper symmetrically relative to the rail.
For now, two drawbacks remain: can not remove the pencil and the support of markers tends to twist and distort the drawing.
To overcome these shortcomings, it takes two to manipulate the object, the first who made the drawing and the second which is guided, the two people paying attention to what are felt in the axis of the diagonal of the diamond. Whoever runs the drawing can also ask his buddy to lift the pen if necessary. My children were happy to try, but it will still have to train in handling.
Fifth, after the course on parallelograms individuals can be asked to demonstrate that the bars form a rhombus and the two markers are always placed symmetrically with respect to the rail.
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