Without such context I had a hard time with the distribution and even the pattern creation for this, until I decided that I wouldn't create space but only create rules. i took a base grid of 1 square meter, and added a unit circle within it. the 4 edge spaces between the circle and the square were consolidated into a diamond-like form and added to one edge of the circle, thus creating an interlocking cell that had an area of 1 square meter still. extending these onto cells of 2, 3, and 4 units, I laid out a grid of progressively larger cells in a roughly circular fashion (in keeping with my circular pattern). I then, quite literally, rolled the dice (or in this case push-pins) to evenly distribute the 10% sub-grade, and 30% paving across the different cell sizes across the space.
This randomly generated base layer left me with a heterogeneous mix of cell types, but i realized that certain relationships existed between different cell types. I decided to take the heterogeneous nature of the landscape and shape it, not by deciding on a cell by cell basis what would be what (no pointing and saying "here shall be ______"). Instead I created a set of rules based on the cellular relationships:
1. All paving cells would stay as paving.
2. Any porous cells sharing a major part of it's edge with a sub-grade cell would become wetland
3. Any porous cells found between 2 paving cells could either be gravel or tall grasses.
4. Any groups of porous cells could become either turf/ground cover or shrubs
Rules 3 and 4 were the only chance for decision making I had. They both give me the opportunity to either improve circulation or create barriers within the space. By applying these rules I found that I often had few choices to make, yet I still had the ability to create rooms and pathways throughout the space using the few choices I had.