Sort Multiple Columns, With Blanks, And Move All Columns Into One

I found this code on Ozgrid to sort all columns of a worksheet that were continuous with no gaps or spaces that works well:

Sub CopyToA()
Do While ActiveCell <> ""
Range(ActiveCell, ActiveCell.End(xlDown)).Cut Destination:=Range("a65535").End(xlUp).Offset(1, 0)
ActiveCell.Offset(0, 1).Select
Loop
End Sub

However, I've tried to manipulate the code myself to 1) find all columns that aren't empty then 2) sort each column individually (WITHOUT expanding the sort to other columns) and 3) combining all the numbers into one seperate column. There are many posts concerning sorting but not one that addressed this particular situation.