  The energetic causal set (ECS) program of Cort\^es and Smolin, whose
distinguishing feature is the foundational time irreversibility of the
evolution equations of quantum gravity, was initiated ten years ago. The model
showed the emergence of a time-reversible phase from the time-irreversible
foundational regime, but originally only had one spatial dimension. The
extension to two and more spatial dimensions has posed a substantial challenge,
the higher-dimensional set of solutions having measure zero (requiring
infinitely-specified initial conditions). This challenge is overcome here with
the extension of the ECS to 2+1 dimensions, invoking a finite interaction
cross-section to determine generation of new events and including an adjustable
fundamental stochasticity. As in the 1+1 dimensional case, we successfully
observe a phase transition into a time-symmetric phase, here through the
emergence of crystal-like structures. Due to the irreversible evolution we also
witness the discrete dynamical systems behaviour of the 1d+1 case explored in
later articles of the ECS program, in which the model is captured in and out of
the limit cycles which here take the form of lattice crystals. In a companion
paper we carry out a detailed parameter investigation and study the causal
network underlying the set, explaining the emergence of the time-symmetric
phase. In a final section we propose a view of science as a (potential) unifier
of threads, and present one such perspective unifying aspects of quantum
gravity, biology, and artificial general intelligence (AGI).
