Here, from a famous set of small piano pieces for small hands:
In these very famous pieces, the right hand is busy with only five notes at a time in a piece or section of a piece, one for each finger. The left hand sometimes gets to play with a few more than five. With so few tones available, and each tone consequently subject to frequent iteration, we should be able to settle quickly into a comfortably familar neighborhood of the tones used singly, in sucession or in combination . But the composer always manages to surprise, bringing out unexpected depth in what would initially appear to be a rather shallow field of possibilities. The chord above to which the forefinger is pointing is a case in point. Yes, this is music about exquisite — and, sometimes, exquisitely familiar if not banal — voice leading, and habits of voice leading should excuse the b in the left hand as a neighboring tone, just passing by, but we do also hear this coincidence of lines as a chord, in its context, and as a very special chord indeed, perhaps the most sonically dissonant possible assembly of three tones extractable from this collection. Such clear means, such reduced materials, and yet such a complex sensation, at the limits of our tonal sensibilities, conditioned as they are by musical experience and probably some neurological hard-wiring. Okay, this is not The Famous Minimalism, and there are other things going on, especially in the realm of metre and accent, but the impulse is the same: simmer, reduce, and the materials are given a new context or frame, one in which we can pay attention to details that would otherwise get (dis)missed.
Or this: I've recently been playing through Charles Shere's sonata ii: compositio ut explicatio (related to a lecture by Gertrude Stein, Composition as Explanation and, in one version, playable as accompaniment to a rhythmicized performance of that lecture). This is a large-scale work for solo piano, about an hour in duration, with a particular wealth of variety in registration and texture. The generous scale of the work and the way in which similar figures and textures are almost rhetorically deployed over its course are so engaging that it scarcely registers that the piece only uses the white keys.* There is almost too much material in those seven pitch classes. Additional chromaticism, given the variety of gestures and textures, would probably be a distraction. Again, simmer, reduce until the flavor is more intense than the sum of the ingredients.
** This is also a Stein reference, in that the writer liked to improvise on the white keys only. Virgil Thomson's Piano Sonata No. 3, written for Stein, is also a white key piece. Another large-scale work for the white keys only is John Cage's Four Walls. These pieces would make a swell program (hint hint).