Adding rows dynamically via macro
 

Hi,

I understand that if I add 4 rows from row 17 onwards, the command
reads as follows:

Sub Insert()
Rows("17:20").Select
Application.CutCopyMode = False
Selection.Insert Shift:=xlDown
End Sub

I would like to modify this for 2 scenarios:

Scenario 1: Now, what if I don't specify 4 rows, but I want it to read
the number-of-rows-to-be-added from a certain cell from a different
worksheet eg: T4 or cell(4, 20) from worksheet 2, because that number
is to modifiable?

Scenario 2: What if I want to add 4 rows, but not necessarily from row
17 - instead, I might want to add 4 rows from any initial row?

Scenario 3: Now combine the 2 scenarios. What if for row 4, I want it
to add a number of rows specified in cell(4, 20) and then for row 5, I
want to add a number of rows specified in cell (5, 20) and so on, for
100 times?

Thanking you in advance.

SD