Create Block Definition

Home tab > Block panel > Create

Name: Chair

Base point: Pick point

Pick the midpoint of the front line

Retain option

Objects: Retain
Behavior: Allow Exploding
Description: Desk Chair
Click Select objects

Cross-select the chair

9 objects selected
An image display beside the block name
Click OK

All parts of chair remain separate

Convert to Block option

Add a line below the arc

Name: Home Chair
Pick the same base point
Objects: Convert to Block
Check Scale uniformly
Description: Home chair with cushion
Clock Select objects

Cross-select the chair

10 objecte selected
An image display beside the block name
Click OK

All objects group into one
A grip show the insert point of the block

Delete option

Delete the right and left edges
Draw arcs by Start-End-Radius 1100

Start the blcok Create command
Name: ECO Chair
Pick the same base point
Objects: Delete
Uncheck both Scale uniformly & Allow Exploding
Description: Office chair with ECO leather
Click Select objects

Cross-select all parts of the chair

10 objects selected
An image display beside the block name
Click OK

The block delete from the drawing

Create another block
Name: Door
Base point: lower-right corner of the rectangle
Objects: Convert to Block

Object Options

Retain: Retain the geometries as seaprate, so can modify and create another similar blcok
Convert to Block: Use the block after created
Delete: Delete block from the drawing, so got more space to draw or create blocks