Take the square cake, place extra piece of cake on top to make hill shape.
Cover with green fondant icing, rolled out thinly.
Colour some icing grey to make road, and add on white road markings.
Make icing roses. make grass by pressing green icing through a sieve or tea strainer.
Make car out of fondant icing too.
I made a mess of the writing, so I printed it our on a sheet of paper and stuck it on....remove this before eating of course!