Auto/Visual Lisp

Retrieving/setting variables is quite simple. If you haven't yet, start looking through all of the variables. Check the following, because I may mispell a few.
;store current settings (setq clay (getvar "CLAYER") cltp (getvar "CELTYPE") ccol (getvar "CECOLOR") );setq ;set to desired values (setvar "CLAYER" "MyLayer") (setvar "CELTYPE" "HIDDEN") (setvar "CECOLOR" 120)
;your pline creation code here ;this can actually be a little complicated
;being polite, set them back to their old setting (setvar "CLAYER" clay) (setvar "CELTYPE" cltp) (setvar "CECOLOR" ccol)
A note on layers: If you want to make sure a layer is available, use the command line layer command's make option. This will create the layer if it doesn't yet exist. Not very elegant code, but extremely effective.........which (IMO) should be the point.
(command "-layer" "M" "MyNewLayer" "")
You could/should probably set color/ltype options for the layer here as well.
Great (actually an understatement) book for a beginner. If I could find mine, I'd send it.