Volume XXIX

VOL XXIX

Geombinatorics Quarterly

Issue 1 (July 2019)

Editors Page   4
New Essays    
Polyominoes with maximally many holes By Matthew Kahle and Érika Roldán     5
Generalizations of the No-Three-in-a-Line Problem By Dustin LaFollette and Anant Godbole 21
The Smallest Art Gallery Not Guarded by Every Third
Vertex		 By Ralph Morrison      24
The International Mathematics Union Abacus Medal By Alexander Soifer    33
On a Geometric Proof of Sums of Powers By Joseph Zaks 37
Recent Books   42
Subscription Form   43

Issue 2 (October 2019)

Editors Page   48
New Essays    
Coloring Distance Graphs on the Integers By Matthew Ellison, Joseph Johnson 49
Fission of Halving Edges Graphs By Tanya Khovanova and Dai Yang 56
4-Regular Planar Unit Triangle Graphs without Additional Triangles

By Mike Winkler, Peter Dinkelacker, and Stefan Vogel

 72
Dynamic Triggering of Earthquakes: Symmetry-Based Geometric Analysis

By Laxman Bokati, Richard Alfaro, Aaron Velasco, and Vladik Kreinovich

 78
Recent Books   89
Subscription Form   91

Issue 3 (April 2020)

Editors Page   136
New Essays    
A 3-Regular Matchstick Graph of Girth 5 Consisting of 54 Vertices By Mike Winkler 116-121
Graph minimization, focusing on the example of 5-chromatic unit-distance graphs in the plane By Jaan Parts 137
Generalizations of the No-Three-in-a-Line Problem A Square-Grid Coloring Problem By Matthew Kahle, Francisco Martinez-Figueroa, and Alexander Soifer 167
Recent Books   185
Subscription Form   187

Issue 4 (July 2020)

Editors Page   4
New Essays    
A small 6-chromatic unit-distance graph in R3 By Aubrey de Grey 5
Polyiamonds Attaining Extremal Topological
Properties, Part I		 By Greg Malen and Érika Roldán 14
What percent of the plane can be properly 5- and
6-colored?		 By Jaan Parts 25
Moral Principles for My Young Colleagues, or
A Tale of Big Man and Little Bird		 By Alexander Soifer    40
New Subscription Form   47