Stewart Coffin is recognized as the world's best designer of polyhedral interlocking puzzles. Before he started exploring beyond the world of orthogonal (all of the pieces are at right angles to each other) puzzles, there were very few examples to be found. To date, he has more than 180 original designs to his credit. A few have been commercially produced in plastic. Most notably, Hectix. His book, The Puzzling World Of Polyhedral Dissections, is a definitive work on interlocking puzzles having a geometrical theme.
In a few cases, Stewart has discovered a simple, but beautiful design and carried it to the extreme with amazing results. It reminds me of Bolero, which starts out with a quiet melody and builds into a frenzy at the end. A good example, is where he went with the Diagonal Burr. Many of his puzzles are variations of this simple puzzle and are by no means a complete representation of variations. Most are composed of six pieces having similar internal structure. The variations are created by adding or removing "blocks" to the ends of the pieces. The most surprising are the Diagonal Cube and the Broken Sticks puzzles.