Doctor Who: 14 Cool Details Revealed In Steven Moffat's Wedding Of River Song Commentary
6. Moffat's Word Processor Couldn't Handle All The Tally Marks
Bit weird, this one. There are a lot of tally marks throughout Series 6, and bizarrely, this actually caused issues for Moffat while he was scripting certain episodes.
This is because his word processor just couldn't do tally marks. For some reason.
He says he had to download another font just to be able to type them out (which resulted in even more problems after printing), although quite why he needed to do this in the first place is anyone's guess. Wouldn't writing "the Doctor's arm is covered in tally marks" be enough?
On the plus side, there are fewer tally marks in The Wedding Of River Song than there are in Day Of The Moon, so presumably, writing this episode went a lot more smoothly.