I'm trying to create a second sheet or a place on the original sheet where I'm holding a backup of data.  I would like Sheets to copy data which was entered into another set of cells, but if the original cells are deleted or a blank is entered, the already backed up data won't be erased.  If new data is then entered into the blank cell, I'd like the backup to change to reflect that.Any idea on how to go about doing that?Here is a sample dummy spreadsheet.
Internal backup within a spreadsheet in Google Sheets
google spreadsheets