Fountains can be angled if you intend to create a v-shape or similar. You can either angle the base board you use and stake accordingly, or build a wooden base with the required angles.
Fountains also work well if they are raised, including novelty fountains such as those which spin. When raising a fountain off the ground you will need to ensure it is 100% secure and is not going to fall over. Cylindrical fountains can be gaffa taped to a stake, other fountains should be placed on a wooden platform which is secure and allows the fountain to be taped in place.
Unlike cakes and candles which shoot projectiles, fountains only emit sparks so they’re a great firework to work with if you want to get even more creative. Members of our Fireworks Forum have done all manner of ingenious set-pieces with fountains including building big wheels, putting them on rocking or spinning platforms, or creating huge star shapes, such as shown below: