I posted this a few days ago on a different thread but didn't get any response, so instead of highjacking that thread I thought it best to start a new one.  The issue is very simple, I created two 2D polygons and wanted to combine them (using the menu command, Compose) and then extrude it.   PROCEDURE Test; VAR     poly1, poly2, polyOut : HANDLE;     TF : BOOLEAN; BEGIN     Poly( 0,0, 10,0, 10,10, 20,10 );     poly1 := LNewObj;     Poly( 0,0, -10,0, -10,10, -20,10 );