Suppose you generate random chords of a circle, with endpoints selected uniformly over the circumference, rejecting any chord that crosses a previously generated chord. The disk is then partitioned into regions bounded by chords alternating with circular arcs. For example, here are $n{=}100$ random noncrossing chords, with a region bounded by 5 chords highlighted (in green). <br />![alt text][1] <br /> I am interested in the statistics of the structure of the dual trees for these regions. Assign each region a node, and connect two nodes by an edge if they share a chord. In the example above, the highlighted region's node has degree 5. Example questions: What is the expected maximum degree of a node for $n$ chords? Making a max-degree node the root, what is the expected height of the tree? (In the example above, the height is 21.) Etc. Has anyone encountered this model before? Or a model sufficiently analogous to help establish these statistics? Thanks for any pointers! [1]: http://cs.smith.edu/~orourke/MathOverflow/Chords100.jpg