Neatly showing why when all you have is two data points you can’t just assume the best fit function for extrapolation is a linear one.

Mind you, a surprisingly large number of political comments is anchored in exactly that logic.

Doubling every three months is an exponential Interpolation and not a linear one!

Good point and well spotted!

PPS: Found it - it’s a “geometric progression”.

A terminology that I learned from the Terminator 2 movie. Only that was, I think, a “geometric rate”.

Chessboard and rice