The irony is that this meme works in reverse for that. At least, in order of mind blowing as I refreshed my memory, it goes multiplication (very easy), dot (scalars easy), cross (vectors medium) and convolution (integrals hard).

In fact, I never did the later two but convolution looks fun.

I see multiplication in code, Cartesian product, multiplication, multiplication.

I might not count as a mathematician though. If the * was supposed to be convolution the a should have been cursive.