I have been reading about binomial coefficients in Wikipedia.
Where there is a visualization of binomial expansion up to the 4th power:
I do not understand the sequence for the 4th dimension, i.e.: $(a+b)^4$
My brain simply does not get it...
For example, take $4a^3b$ and and the orange sketch.
$6a^2b^2$ and the green one.
$4ab^3$ and the light blue one.
How do they map to each other?
Could someone give some hints how to get that?