Rubber banding: press the left mouse button
    and release when the rectangle is of appropriate
    size
        %%
    drawtool \$this.draw 
    \$this append \$this.draw 
    \$this.draw create rectangle 20 20 80 80
    \$this.draw create rectangle 10 30 70 90
    \$this.draw create oval 40 40 90 90
    \$this append \$this.draw 
    %%
    For additional information click on the %% 
    button \$this.goto -text instruction -command end-of-text
    \$this append \$this.goto
    %%
    button.  Press %%
    button \$this.quit -command { destroy . } -text quit -bg pink
    \$this append quit
    %% to remove the window.