In Class Note

to create a layer,
can type comma to sepreate each new layer

anytime when type space, means enter

to create more than one layer in once
in notepad:
layer
n
a-wall,a-glaz,a-flor,a-clg


no space after comma

different color, linetype, anything is different, using different layer
can be create a lot of layers in autocad

0 layer and the current layer will never be deleted

click on the object
command: li (list) - select object - enter
then will shows the info of the object

chage prop
command:
-ch
select object
p
la
layer name

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command: tr
delete the selected line indepantance