So, in Illustrator, there's a tool called the free-transform tool (shortcut is E), and while stretching an object, by holding control, it changes to the perspective stretch (allowing me to pull just one corner). The perspective stretch is sometimes neat, but I don't always want it. Sometimes I just want a generic stretch. But I can't find online or anywhere in the program how to do a basic free transform. E.g.:
That's not so much a transformation as it is a distortion. Transforming alters the entire shape, whereas distortion only alters a portion of the shape. All "transform" operations tend to alter everything at least to some minor degree.
If you want the second example just draw an angled shape above the rectangles and use the Pathfinder Panel to subtract the tops of the rectangles.
I suppose you could also use an envelope to distort things. Or group the rectangles and use
Effect > Distort & Transform > Free Distort