Tipster Leon Joy shares a tidbit he discovered about angle rotations in AutoCAD.

"When I was performing a Rotate command, I mistakenly typed an N at the prompt for an angle to rotate. The Rotate command worked without an error. After some experimenting I discovered that, instead of typing in a number for an angle, you can type N for 90°, W for 180°, S for 270°, or E for 0/360°. It appears to also work with other commands whenever an angle is required."

Notes from Cadalyst Tip Reviewer Brian Benton: These are the compass variables: N is for north, S for south, etc. By default, AutoCAD's zero angle is due east, or to the right horizontally. Therefore, up — or 90° — is north. If you want to rotate an object 90°, type in 90 degrees, or just the letter N. It won’t rotate the object to the north; it rotates it 90° instead.