Improvisations using harmony interfaces

I made a simple piece of music in Piano roll. There are two parts, one for harmony and one for the beats. I think this is pretty easy for a green hand to compose by themselves. All notes are presented as block units and very clear to see the pitch intervals which is convenient to make harmony. What else interestin is that I found I can easily switch from C to D, from major to minor or others avoiding making the exist harmony sound weird. 

In the other website Circle of fifths, harmonies are already set. However I think this is really enjoyable with its great interface. The outer circle controls majors and inner circle controls minors. When switching to a major or minor, color of lines above which stands for the pitches would also change to relevent color whit the circular sector. Speed is also under cotrol. I love the patterns of a walking man and a running man which stands for slow and fast.