How to construct the commons with the power of play? How to reactivate leftover public spaces in central Bogota by architectural interventions that stimulate playful actions? I shift my focus from buildings to the ground surfaces, and redesign them into a constellation of “2.5D architectural composition”. “2.5D” refers to an abstract composition of the ground surface, including composing different ground materials on the planer dimension (2D), and create minor vertical level difference by sinking, elevating, folding and undulating (0.5D). These compositions become abstract playgrounds. They should be unconventional as the playful quality is achieved by manipulating the ground surface rather than adding playful objects. Yet, they are humble as the minor level difference and usage of familiar materials enable them to merge into the local context. I expect that these “2.5D playgrounds” will bring Bogota citizens together, stimulate their playful actions, and enable them to recognize the scattered playgrounds in the city as a constellation of “playful commons”.