Every object you draw has properties. Some properties are general and apply to most objects; for example, layer, color, linetype, and plot style. Other properties are object-specific; for example, the properties of a circle include radius and area, and the properties of a line include length and angle.
Most general properties can be assigned to an object by layer or can be assigned to an object directly.
For example, if a line drawn on layer 0 is assigned the color BYLAYER, and layer 0 is assigned the color Red, the line is red.
For example, if a line drawn on layer 0 is assigned the color Blue, and layer 0 is assigned the color Red, the line is blue.