Do you want to build a snowman? (Scrum style)

The basic principle of scrum, is to deliver the absolute bare minimum to make a product do its job, and then develop it incrementally over a number of short sprint periods.
 

Start basic, and then go back to add the bells, whistles, nice to have features and extras afterwards.

It's also worth mentioning that these sprints don't have to run back to back - it's ok to work on other things in between - particularly if this gives your customer time to think about what they need, or find out more information (like decide what colour scarf they'd like)
 

	So if my product is to draw a snowman - in the first sprint I do the minimum possible to make it recognisable Imagine it's pictionary!
	In sprint ii you can start to think about the other features of a snowman, so maybe the hat and scarf, and buttons. As you only have a set amount of time, you'll need to weigh up how much you want each item against how long it will take to implement. In this sprint we could only achieve buttons and a hat, no scarf, so that rolled forward to the next sprint.
	In sprint iii scarf was the top priority, but we also had enough time to start adding "extras" such as stick arms.
	By the time you reach sprint iiii and iv you've already got a well established product. Potentially you should have already stopped, and moved on to something else. However, if you have the business need and the time available - why not add some colour and other embellishments. Just make sure that these do benefit the customer, or at the very least do not irriate people or inhibit use of more essential features.