As requested by Kaz and approved by the voters here on meta, questions asked on Code Review that do not contain code are now blocked.
I've configured this initially as a three-line minimum (or three separate bits of code-formatted text, or any combination of the two). This may be too much; it may more easily be too little. Happy to change it to anything else y'all decide is right.
If insufficient code is included in the question, a small error is shown below the editor:
This links to https://codereview.stackexchange.com/help/how-to-ask, which seems like a fairly comprehensive set of instructions on the matter.
As with the code formatting check and the code/explanation ratio check, this only applies to users at or below 200 reputation.
Please let me know if you have any questions or encounter any problems with this.