Stretching lines
When you select a line whilst in standard draughtong mode with the cursor looking something like 
. You can
select objects and they are changed in appearance to dotted with grip squares at particular constructional nodes like end and
mid point.
Moving the cursor over one of the grips and clicking causes the computer to switch into stretch mode. You notice that the grip has
changed colour. It is now attached to the cursor and will tag along wherever the cursor goes.
Notice that the object snap locks to other nodes.
This is a handy facility for modifying objects. A stretch command is provided that allows you to select a number of grips at once.
This enables you to move complete chunks of a drawingat one time rather than one node at a time.
Selecting the Stretch command requires that you place a box around the NODES or GRIPS that you want to move.
To include the nodes or grips you MUST form the box as an inclusive box. That is, a selection box that selects everything it
touches as well as everything inside. To do this you MUST form the box by clicking the first point to the RIGHT of the objects you
want to select and dragging to the left. You notice that it is dotted and if you drag to the right of the fisrt point it becomes
solid signifying that it is exclusive and only contains objects that are completely contained inside the box.
The nodes have been selected and the small selection cursor is awaiting further selections but there are none to add so you would
press enter.
Once the nodes have been selected the action is identical to the earlier process for one node.
