This chapter presents an informative summary of the big contribution Sophus Tromholt gave to the world of matchstick puzzles. In the Year 1889 Tromholt published book “Matchstick games. Mental exercise and entertainment”. It was largely dedicated to matchstick puzzles, expanding significantly their forms and number of involved matchsticks. Tromholt shaped the world of matchstick puzzles because numerous of his puzzles were repeated by many posterior authors (Chap. 6 ). Additionally, in a few puzzles, Tromholt announced after formulation the number of sought different solutions. These solutions were presented in the solution section. From the first to the fifth edition, published in 1892, the number of such puzzle increased from three to twelve. Nevertheless, in many other multiple-solution puzzles, Tromholt published only one solution. Four examples of the “cognitive bias of one solution” are presented for the puzzles that were not repeated by posterior books authors. In their analysis is shown how it is possible to construct additional fundamentally different solutions from a found solution.