Ten.

For harp.

I don't know a single harpist, but in theory it should be playable.

click the image for a clearer view

The weird lines at the top of the score represent the pedal positions. There are three pedals on the left, four on the right, representing the accidentals for notes in the following order: D C B | E F G A. A pedal all the way up changes that note to flat (all across the harp), a pedal in the center changes it to natural, and a pedal down changes it to sharp. In this case, the D B E G A lines are in the center, meaning natural. The C and F lines are below, meaning sharp. (Had any lines been above, it would have meant flat.)

So, this is essentially using D C# B | E F# G A, or a D major scale. I just wanted to try and mark out some harmonies; something about stacked 5ths (the D A E B chord in the beginning) makes me smile.