DNA

DNA comes with 4 bases in 2 pairs,
((A,T),(G,C))
that make two strands that spiral around each other by using Hydrogen bonds of the pairs.
Thus one strand determines the other.
This makes it very easy to split for cloning.
After the split, the second strands are rebuilt in their own cells.

Complex numbers also come in a similar form,
((-1,+1),(-i,+i))
also forming a rotating cross like DNA bases.
Complex numbers can be represented by two equivalent forms, cartesian and polar,
a+ib=Sqrt(a^2+b^2)*e^(i*arctan(b/a))
where a,b are real.
The unit circle e^(i*a) is isomorphic to U(1), the symmetry group of light.
Light traces a double helix form as it moves in space.

Modular group is also isomorphic to unit circle,
((a,b),(c,d)), ... a*d-b*c=1

All this shows that M2 is a universal set.