(Grid Using Class Rectangle2D.Double) Modify your solution to Exercise 13.13 to draw the grid by using class Rectangle2D.Double and method draw of class Graphics2D.   (Drawing Tetrahedrons) Write an...

the grid by using class Rectangle2D.Double and method draw of class Graphics2D.

(Drawing Tetrahedrons)
Write an application that draws a tetrahedron (a three-dimensional

shape with four triangular faces). Use class GeneralPath and method draw of class Graphics2D.