How do you draw a curved staircase in AutoCAD 2D?

What are the types of stairs?

Types of stairs

• Straight stairs. Straight flight stairs. Double straight flight staircases. U shaped double flight enclosed staircase. U shaped staircase with shaft. Staircases with three or four flights of steps. Imperial staircase.
• Curved stairs. Elliptical stairs. Spiral stairs. Helical stairs.
• Mixed stairs.