To me, solo piano means playing "the whole piano", all registers, two independent hands, pedals, the strings and insides. All these aspects were equally important to me, so I was preparing the disc while practicing in different directions.
I was working on a solo language. Of course I had ideas in my head that I wanted to deepen. Rhythmical independence fascinates me; as for playing inside the piano, I was thinking in terms of different sounds that "speak", in conjunction with sensitivity to silence and rhythmic/dynamic movements. I wanted to integrate these sounds into more "coventional" playing on the keys. In a way, I am interested in transcending the piano's restrictions - the rigid pitch system, the apparent impossibility to do a crescendo on a note or chord. Playing inside helps me overcome these restrictions, it brings me closer to the idea of actually having a string instrument at hand.
On the other extreme, I also like to emphasize the rigidity - the idea of a giant "music box". I find Nancarrow's studies for player piano very inspiring.
from an e-mail interview with Daniel Varela (2006)