Incentive to type

Skye and I have been challenged to find ways to positively motivate Aidan to get in regular practice on his violin. His teacher asks him to only practice for 10 minutes per day. It might be hard to believe this, but even that is challenging when we don't have it built into a daily routine. Prompting Aidan at various times of the day, to practice, hasn't been successful so far. We've considered getting him into another lesson, closer to home, in the middle of the week, but this will cost at least another $80/month, and may require an additional trip to the lesson, if we can't coordinate with Austin's music lesson time slot.
On the way to Aidan's lesson on Saturday, I was inspired to try the same incentive program that was so successful for both boys, when learning to toilet train ... Lego!!! Only this time, it's big-boy Lego. I bought Aidan the Star Wars Separatist Shuttle and Austin the Power Miners Crystal Sweeper.
Aidan earns 19 pieces per day, for 2 weeks and Austin earns 22 pieces per day, for 3 weeks.
Aidan earns pieces each day he practices his violin for a minimum of 10 minutes, and Austin earns pieces each day he practices typing for a minimum of 15 minutes. So far, it's working like a charm.
And we have the side benefit of a lot of math figuring ;) They've been going through the instruction books, to find out how far they'll get "tomorrow," and how many days it will take to get to various stages in the building process. They work out how many pieces they'll have in a week. Austin worked out 7 x 22, by starting with 10 x 22, then subtracting 3 x 22. He arrived at 144, because he had worked out 3 x 22 to equal 76, in his head, so he subtracted 10 too many. Once he realised where he went wrong, he corrected, but accidentally took another 10 off to arrive at 134, and caught himself quickly to change his answer to 154. I worked out the answer by multiplying 7 x 20 = 140 and adding 7 x 2 = 14, 140 + 14 = 154.
This incentive program might be a way to teach our boys a bit of patience, too. They are so accustomed to not having to wait for what they want, and not having to work for it. Not entirely, of course (they do chores to earn pocket money), but Skye and I feel that it's very difficult for our kids to understand what it's like to have to live without things you want, when they seem to be surrounded by such abundance.
Anyway, it is achieving the primary goals to motivate Aidan to practice his violin and Austin to practice keyboarding.