Function: plotdraw
Section: graphic
C-Name: plotdraw
Prototype: vGD0,L,
Help: plotdraw(w, {flag=0}): draw rectwindow w. More generally,
 w can be of the form [w1,x1,y1, w2,x2,y2,etc.]: draw rectwindows wi
 at given xi,yi positions. If flag!=0, the xi,yi express fractions of the size
 of the current output device.
Doc: physically draw the rectwindow $w$. More generally,
 $w$ can be of the form $[w_1,x_1,y_1,w_2,x_2,y_2,\dots]$ (number of
 components must be divisible by $3$; the windows $w_1$, $w_2$, etc.~are
 physically placed with their upper left corner at physical position
 $(x_1,y_1)$, $(x_2,y_2)$,\dots\ respectively, and are then drawn together.
 Overlapping regions will thus be drawn twice, and the windows are considered
 transparent. Then display the whole drawing in a window on your screen.
 If $\fl \neq 0$, $x_1$, $y_1$ etc. express fractions of the size of the
 current output device
