Edsger W. Dijkstra. The usual way in which we plan for tomorrow is in yesterday's vocabulary. Coming to grips with a radical novelty amounts to creating and learning a new foreign language that cannot be translated into one's own mother tongue. The first radical novelty is a direct consequence of the raw power of today's computing equipment. Edsger W. Dijkstra.
Several answers are possible.
I prefer to describe it the other way around. The program is an abstract symbol manipulator which can be turned into a concrete one by supplying a computer to it. After all, it is the purpose of machines to execute our programs. So, we have to design abstract symbol manipulators. We all know what they look like.