HG91012

The steps for the design of this exercise in AutoCAD are as follows:

Command: LIMITS
Reset Model space limits:
Specify lower left corner or [ON/OFF] <0.00,0.00>: 0,0
Specify upper right corner <420.00,297.00>: 80,60

Command: LINE
Specify first point: 0,20
Specify next point or [Undo]:  <Ortho on> 20
Specify next point or [Undo]: 78
Specify next point or [Close/Undo]: 28
Specify next point or [Close/Undo]: 44
Specify next point or [Close/Undo]: CLOSE

Command: REGION
Select objects: Specify opposite corner: 5 found
1 loop extracted.
1 Region created.

Command: EXTRUDE
Current wire frame density:  ISOLINES=4, Closed profiles creation mode = Solid
Select objects to extrude or [MOde]: 1 found
Specify height of extrusion or [Direction/Path/Taper angle/Expression]: 44

Command: RECTANGLE
Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]: 15,0
Specify other corner point or [Area/Dimensions/Rotation]: @14,28

Command: EXTRUDE
Current wire frame density:  ISOLINES=4, Closed profiles creation mode = Solid
Select objects to extrude or [MOde]: 1 found
Specify height of extrusion or [Direction/Path/Taper angle/Expression] <44.00>: 26

Command: SUBTRACT
Select solids, surfaces, and regions to subtract from ..
Select objects: 1 found
Select solids, surfaces, and regions to subtract ..
Select objects: 1 found

Command: RECTANGLE
Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]: 6,6
Specify other corner point or [Area/Dimensions/Rotation]: @32,32

Command: EXTRUDE
Current wire frame density:  ISOLINES=4, Closed profiles creation mode = Solid
Select objects to extrude or [MOde]: 1 found
Specify height of extrusion or [Direction/Path/Taper angle/Expression] <-26.00>: 20

Command: CYLINDER
Specify center point of base or [3P/2P/Ttr/Elliptical]: 22,22
Specify base radius or [Diameter]: DIAMETER
Specify diameter: 20
Specify height or [2Point/Axis endpoint] <-20.00>: 20

Command: SUBTRACT
Select solids, surfaces, and regions to subtract from ..
Select objects: 1 found
Select solids, surfaces, and regions to subtract ..
Select objects: Specify opposite corner: 1 found

Command: UNION
Select objects: Specify opposite corner: 2 found