Graphic option
transparent
Default value: false
false
If transparent is true, interior regions of polygons are filled according to fill_color.
true
fill_color
This option affects the following graphic objects:
gr2d: polygon, rectangle, and ellipse.
gr2d
polygon
rectangle
ellipse
Example:
(%i1) load(draw)$ (%i2) draw2d(polygon([[3,2],[7,2],[5,5]]), transparent = true, color = blue, polygon([[5,2],[9,2],[7,5]]) )$