21 Questions - Card Games by Linear Lab LLC represents a digital adaptation of the classic conversational game, positioning itself as a tool for fostering interpersonal connections through structured dialogue. The iOS application transforms traditional card-based interaction into a mobile experience, offering curated question decks designed to progress from lighthearted topics to deeper philosophical discussions. The application's core functionality revolves around 15 distinct thematic decks containing hundreds of questions categorized by relationship dynamics and conversation depth. Features include customizable game settings, conversation timers, and progress tracking that allows users to resume previous sessions. The interface employs a clean card-flipping mechanism with subtle animations, while organizational tools enable users to bookmark particularly impactful questions for future reference. User experience demonstrates particular strength in social scenarios where organic conversation might stagnate. Real-world usage patterns show high engagement during road trips, date nights, and virtual gatherings, with the app serving as both icebreaker and relationship-deepening tool. The interface maintains minimalistic design principles with intuitive navigation, though some users report occasional desire for more advanced filtering options between question categories. User feedback consistently highlights the app's effectiveness in facilitating meaningful dialogue, with multiple reviews specifically noting improved relationship depth. User 'Dercg' (July 22, 2025) reported 'very happy with the depth we had gone while playing,' while 'Cj____2' (June 30, 2025) found it 'the perfect game to help my fresh relationship find its course.' The 4.67/5 rating reflects overwhelmingly positive reception, though some users note occasional question repetition across extended use. The application demonstrates notable strengths in conversation scaffolding and relationship building, particularly for couples and small groups. Limitations include relatively basic customization options and dependence on participant engagement for optimal experience. Ideal use cases include relationship building phases, social gatherings requiring structured interaction, and long-distance communication where guided conversation enhances connection quality.