In this use, structural steel rebar provides the strength and stiffness to the concrete, while the cured cement holds the rebar stationary. Rebar alone would flex too much and cement alone would crack easily. However, when combined to form a composite, an extremely rigid material is created.
Autodesk ended Vista support in 2012 and the versions 2013 and up are not compatible with Vista. AutoCADu 2008 (and 2009-2012) compatibility applies for both 32-bit and 64-bit versions of Windows Vista Home Basic, Home Premium, Ultimate, Business and Enterprise. For AutoCAD 2007 and AutoCAD LT 2007 Autodesk has released Service Pack 2 which makes them compatible with the 32-bit version of Windows Vista.
AutoCAD 2011 changed the way many grips worked: It added many more options to polylines. AutoCAD 2012 added similar options to most objects in AutoCAD. The Ctrl trick only works in AutoCAD versions prior to release 2011. Hold down the Shift key and select more than one grip. Now when you edit the grips, these selected grips will retain their geometric relationships.