Tony Hoare refers to null pointers as his billion-dollar mistake. Option types, popularised by functional programming languages, provide a much cleaner alternative.
This extension has nothing whatsoever to do with null pointers or option types!
New extension: Options
This extension enables options, which allow a punter to use a river claimed by another punter. Every punter is allowed to buy n options during the game where n is the number of mines. Each river claimed by a punter has exactly one option which might be bought by a second punter.
The rules for scoring are unaffected – but sharing a route with another punter might be a good option from time to time.
You can find the specification here.
Happy punting, and good luck!contest