By trace describe a way how one program leads to its result. If a program is executed by trace, we emphasize it is on a flow of change from the beginning to the end.
- A video game
- A flow or one parameter transformation
The fundamental theorem of calculus by Leibniz, is an example to relate a "program" by trace with the other "program" by effect. The beginning point and the end point of the trace is just the effect.