  We provide a tutorial introduction to the algebraic graph rewriting formalism
PBPO+. We show how PBPO+ can be obtained by composing a few simple building
blocks, and model the reduction rules for binary decision diagrams as an
example. Along the way, we comment on how alternative design decisions lead to
related formalisms in the literature, such as DPO. We close with a detailed
comparison with Bauderon's double pullback approach.
