First, we show how to use points.

The construction window below should show  two crossed lines. At the top left of the window are three icons that corrspond to the "Point," "Delete last object" and "Object color" tools respectively (if you hold your mouse over the tool icon, the tool's name will display).

  • The "Point" tool creates points (naturally)
  • The "Delete last object" tool  undoes the last construction step
  • The "Object color" tool sets the color of the next  object  that is created (at this point, we can only create points)
To become familiar with these tools, please follow the instructions below

 

Select the "Point" tool by clicking on it. 

Generate a few points by clicking at random locations in the construction window with the left mouse button.

Move some of the points around by dragging them with the right mouse button.

Move the mouse over one of the lines. A "preview dot" will appear on the line. If you left click, the preview dot becomes a new point. Drag the new point with the right mouse button. It can only move along the line.

Move the mouse to the intersection of the two lines. Both lines will highlight as you approach the intersection. If you left click at the intersection, this new point cannot be moved at all. It is fixed at the intersection.

Click the "Object color" icon so that the color changes, then create colored points in the white area  

Right click on an existing point (be careful not to move the mouse as you click). A dialog box will open that allows you to change the point's properties:

  • Change the  point's name to Q by typing "Q" in the first field.
  • Change the point's shape to "X" by clicking on the "X" in the last row of icons
  • Display the point's name and location by clicking on the second and third icons in the second-to-last row of icons.
  • Click "OK" to make your changes take effect.
If you hold the mouse over any icon, the corresponding function will display.

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