Two Simple Pebbling Puzzles

Pebbling is a game where pebbles are placed on the vertices of a graph. A move occurs when one takes two pebbles from a vertex, discards one, and places the other on a connected vertex. A more detailed description can be found on Wikipedia - https://en.wikipedia.org/wiki/Graph_pebbling In these simple puzzles the vertices are represented by shallow bowls and the connections, edges, are rods. To begin the puzzles two pebbles are placed on each vertex. The problem is to make moves so that a single pebble is left on the central vertex. An stl pebble file is included although any collection of small objects can be substituted. OpenSCAD code is provided.