Citypedia is an architectural creation game that allows players to discover how different urban patterns are generated and how they affect the organisation of architecture. Players create their own unique city by combining both patterns and form, drawing out configurations of city blocks and rearranging building typologies. Drawing from research into historical city forms, the game allows players to experiment with cities using orthogonal, radial, and Voronoi grids, that are recomputed in real time and procedurally regenerated as the urban patterns change. Players experiment with different skylines and city formations, creating palimpsests built upon previous design decisions. At the scale of buildings, players use tools to reshape individual units, with changes cascading through unit typologies. By combining procedurally generated and player driven systems, Citypedia playfully explores the unexpected quirks and spatial frictions that cities collect over time. The game examines how cities can be planned with an overall vision in mind, but inevitably find themselves transformed and disrupted over time, with their future forms defined by ever more granular and emergent forces.