Snap
Snap works in two modes:
| • | Snap to Entities: |
| o | lines, line centers and intersection points; |
| o | ends of lines, arcs and splines; |
| o | centers of circles and ellipses. |
| • | Snap to Inserts - block's insert points. |
Snap to Entities 
button on the toolbar switches on or off snap to entities mode.
Snap to Inserts 
button on the toolbar switches on or off snap to the block's insert point mode.