Euclid vs fractal

Piggy knows little about fractal geometry. It’s said that the occurrence of fractal geometry is due to the perception of microscopic things: for example, a ruler seems very smooth and straight, but in microscopic, it’s ragged. So, people wonder if the concept of a straight line is artificial (actually not exist in nature)…then, Euclid geometry is idealized.
Piggy’s humble opinion is as below:
According to Newton’s first law, when the joint forces equals to zero, the object moves in a straight line due to the inertial. So, a straight line is meaningful when it is used to describe trajectory of movement.
In respect of microscopic issues, I encountered such an odd point elsewhere: some people consider that fundamental particles have no shape and size! In fact, the concept of “mass point” is abstract. If fundamental particles have no shape and size, where does the macroscopic shape and size come from?