Control the Color and Linetype Properties in Blocks

There are three choices for how the COLOR , LINETYPE , and LWEIGHT properties of objects are treated when BLOCK is inserted:

Retain their original properties. For this choice, it is recommended that you set the properties individually for each object in the block , not use BYLAYER and BYBLOCK properties.
Inherit properties from the layer on which they are inserted. For this choice, you should set the current layer to 0, and set the current color, linetype and lineweight to BYLAYER before create objects of the block.
Inherit the current properties settings of the drawing. For this choice, you should set the current color or linetype to BYBLOCK.