VBA. Move data from certain columns to another sheet, stacked up

Hi

I'm after a VBA code that would scan the following ranges below on the sheet called "Data":

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It would look at these columns and copy over information from row 2 downwards (in order to exclude the headers). Now the data in these columns will be dynamic in terms of number of rows of information. It can be zero to couple rows. The code should use the the first column of the range to determine the row count.
e.g. with "R:T", it would be column "R" to determine the row count.

I would like the code to take the data within these columns and copy them over to a sheet called "output" and neatly stack them up in column "A:C".

I have done an example workbook together with sheet called "Example Output" so it is easier to understand what the desired outcome is. I have highlighted these columns in yellow and the data that should be copied over as in green.

I would appreciate if someone could offer me the most efficient code that you can think that would achieve the desired outcome.
Any help is genuinely appreciated.
Cheers
Rain

Hi JBeaucaire
Spot on! Very clever stuff.
Thank you.