Design Pattern: Strategy pattern (Tarif)

[Github code](https://github.com/bethrobson/Head-First-Design-Patterns) [Design Patterns for Humans](https://github.com/kamranahmedse/design-patterns-for-humans#-strategy) - Secondary source [Session Notes](https://gist.github.com/fmtarif/beeceec9aedc36725e358b077cb1276a)