Numbers Puzzle started 14 years ago, in the Android 2.x days, as one of my early Android development learning projects. I wanted to recreate the classic 15 puzzle while learning touch controls, layouts, and game logic. What began as a simple exercise grew into a polished sliding number puzzle with tap and swipe gameplay, full row and column moves, helpful tile highlighting, pause and resume, shuffle, and different board sizes. It keeps the classic goal simple: arrange the numbers in order and leave the empty space at the end. For me, it is both a timeless brain teaser and a piece of my Android development history.