## Tangram

### Applet instructions

Moving the pieces

The seven tangram pieces can be moved through free translation and rotation by multiples of $$\frac{\pi}{8}$$.

In order to make a translation, drag the piece while clicking on its center. The rotation is controlled by the dot on one of the piece's vertices. Furthermore, you can also reflect the parallelogram, moving the blue dot at the upper right corner.

Choosing the figure

Choose a figure in the vertical segment on the sidebar, dragging the dot over the segment.

The shadow image of the chosen figure will appear in small size at the applet's upper right corner.

In the playing area there is a highlighted black dot, which corresponds to the marked point in the smaller image. In order for the constructed figure to be recognized, the puzzle must be built bearing in mind that point's position. In that way, when the pieces layout is close to the considered solution image (or its symmetrical), you get a notification saying that the puzzle is correct. Notice, however, that the applet's solution image represents only one of the possible configurations.

Start

At the small segment start, you can reset the pieces to the initial position.

Game options

In the horizontal segment at the end of the sidebar, you can choose different game options, corresponding to decreasing difficulty levels, gradually simplifying the solving process. You should start with the first option (free building), since it is the least guided one, and change options only if you need help. Particularly, you should only use the solution as a last resort.

Free building

You may solve the puzzle using only the shadow image at the corner as a reference.

See figure

You can opt to display in the playing area a figure similar to the shadow image at the corner. If you click on that option, a vertical segment will appear on your right side, which allows you to control a scale point of the figure of the playing area, in order to manually adjust its size to what you think is the real size.

View full size

With this option, the figure in the playing area will appear instantly in the right size, according to the pieces displayed on the playing area.

see solution

Finally, the last option enables you to see a possible configuration for solving the puzzle.

Observations:

• The presented and recognized solution is only one of the possible configurations to solve the puzzle.
• In order to strengthen your persistence ability, in some examples not all game options are available.