Kumulator - The idea
Aim: easy to use learning environment.
Define a state A (variable) and the stock (start value of A) and define the change rate vA by a term.
New stock = old stock + change.
It is the fundamental idea of accumulation. Diagram:
Blue cube: Container. State A, variable A.
Green circle: Valve. Change rate.
One state - one change rate!
Step by step: Discrete calculation and plotting points.