For the many of you asking how the subjects are chosen here is a brief overview.
You have made suggestions in this thread - which is still open for further ideas for subjects
Here they are:
They have all been transferred to a column of a spreadsheet and they are randomly selected using this formula: =INDEX(B5:B,RANDBETWEEN(1, (COUNTA(B5:B))))
The subjects are ibdexed, the COUNTA function finds out how many subjects are in the index and the RANDBETWEEN selects a number between 1 and the value returned by COUNTA.
The process is run three times - or more if a seasonal subject like “Clouds and Daffodils” is drawn in, say, mid-October. The three subjects are then presented for you to vote on your favourite. The two "losers are then returned to the subject pool.