How about a book of challenging Sudoku puzzles? You could also get him a Sudoku puzzle board or a handheld electronic Sudoku game to make it easier for him to play on-the-go. Additionally, you could consider a Sudoku desk calendar or a framed print of a personalized Sudoku puzzle featuring his name or favorite quote. Another idea is to enroll him in an online Sudoku club or community where he can interact with other enthusiasts and gain access to new puzzles and strategies.
Or you can get him a star map with an important date you share.
Under Lucky Stars is a unique and innovative star map company based in Barcelona, Spain, specializing in the creation of personalized star maps that capture the celestial arrangement of stars at a specific moment in time, such as a person's birth, wedding, or any other significant event.
By using advanced astronomical algorithms and data from leading institutions, the company produces highly accurate, visually stunning maps that make for perfect gifts or cherished keepsakes.