  This paper is a `spiritual child' of the 2005 lecture notes Kindergarten
Quantum Mechanics, which showed how a simple, pictorial extension of Dirac
notation allowed several quantum features to be easily expressed and derived,
using language even a kindergartner can understand. Central to that approach
was the use of pictures and pictorial transformation rules to understand and
derive features of quantum theory and computation. However, this approach left
many wondering `where's the beef?' In other words, was this new approach
capable of producing new results, or was it simply an aesthetically pleasing
way to restate stuff we already know?
  The aim of this sequel paper is to say `here's the beef!', and highlight some
of the major results of the approach advocated in Kindergarten Quantum
Mechanics, and how they are being applied to tackle practical problems on real
quantum computers. We will focus mainly on what has become the Swiss army knife
of the pictorial formalism: the ZX-calculus. First we look at some of the ideas
behind the ZX-calculus, comparing and contrasting it with the usual quantum
circuit formalism. We then survey results from the past 2 years falling into
three categories: (1) completeness of the rules of the ZX-calculus, (2)
state-of-the-art quantum circuit optimisation results in commercial and
open-source quantum compilers relying on ZX, and (3) the use of ZX in
translating real-world stuff like natural language into quantum circuits that
can be run on today's (very limited) quantum hardware.
  We also take the title literally, and outline an ongoing experiment aiming to
show that ZX-calculus enables children to do cutting-edge quantum computing
stuff. If anything, this would truly confirm that `kindergarten quantum
mechanics' wasn't just a joke.
