Jordan's direct notation

As anecdote from Littlewood's Miscellany:

"It was said of Jordan's writings* that if he had four things on the same footing (as a, b, c, d) they would appear as

a, M^'₃, ε₂, Π^''_1,2."

*Jordan was a famous French mathematician, most known for the Jordan Curve Theorem which proves that a closed curve drawn on a sheet of paper divides the sheet into two parts that can be suggestively called the interior and the exterior of the curve. Trust me it is a hard one to prove.