This study developed and evaluated the initial feasibility of Make the Sequence, a physical board game adapted from tic-tac-toe to support Grade 11 students' engagement with trigonometry. The product was designed in response to teachers' need for reusable, low-technology learning media that connect problem-solving, peer explanation, and strategic play. The study used an educational research-and-development design organized through the ADDIE model. The analysis phase identified trigonometric functions, the sine and cosine rules, and trigonometric equations as topics requiring more interactive practice. The design and development phases produced an 8 x 8 magnetic board, team chips, 64 trigonometry problem cards, special action cards, and a facilitator guide. The prototype was reviewed by a mathematics content expert and a media design expert, then tested with 24 Grade 11 students. Expert validation indicated that the prototype was appropriate for classroom use after minor revisions related to title visibility and board-edge contrast. Classroom observations showed that the game supported turn-taking, visible participation, peer discussion, and facilitator-guided feedback during problem solving. Because the study did not use a control group or a pretest-posttest achievement measure, the findings are interpreted as evidence of content validity, usability, and classroom feasibility rather than as evidence of learning effectiveness. The article contributes a replicable design specification and formative evaluation argument for future studies of non-digital game-based learning in secondary mathematics.