various issues in examples

* validate-parameter still present
* polygons should be drawn in reverse order, otherwise you can't see/access the smaller (lower) one

Start by locating the examples containing the still-present validate-parameter usage and the polygon drawing logic. Confirm the intended example behavior from the issue: remove the obsolete usage and draw polygons in reverse order so smaller, lower polygons remain visible and accessible.

Written by the indexing model from the issue text.