This intricate puzzle is different to any we've seen before and wonderfully challenging! Like Sudoku in a puzzle! As a difficulty benchmark, I (age 41!) can do the small one in 5-10 minutes but my 6-year-old is challenged by it. The medium one I reckon would take me an hour (but we have a few reports of 10-11 year olds managing it in 15 minutes!), and the large one takes adults quite a few days if not longer (except one lady did it in an hour, people are amazing!). What it contains: A novel wooden puzzle with its own wooden storage cover. 0.5cm thick and: Small: 17cm wide, 20cm high. 7 pieces Medium: 25cm wide, 29cm high. 19 pieces Large: 32cm wide, 37cm high. 37 pieces  Feel great about where it comes from: Raw materials from Europe? Poland - Yes Organic? TBC Manufactured in Europe? Yes - Poland What's it made from? FSC-certified birch plywood, varnish recommended for toys, natural coconut oil. What's it packaged in? Nothing! Shipping packaging from manufacturer to us: Plant-based packing peanuts, cardboard box, recycled paper Plastic-free? Yes 100% Vegan? Yes Animal-cruelty-free? Yes Reused upcycled or recycled? No - new wood Feel great about where it goes after you've used it: Biodegradable compostable? Yes 100% Reusable refillable? N/A Recyclable? Yes! Feel great about you and your child using it: Great for ages: 3+ Shelf life: Indefinite Awards: 1st place: 'Child-Friendly World' competition 2019 (Poland's oldest toy competition); 1st place eco company in Baltów; Be the Change! competition; among others Safety standards met: relevant European standards for toys (CE-marked) Solvent-free? Yes Gluten-free? Yes Peanut-free? Yes Soy-free? Yes Lactose-free? Yes Easy to wash-off clothes skin? N/A Improvements we're working on in this product: None, we think it's perfect! But let us know what you think! Search terms: logic puzzle, geometric sudoku, Stuka Puka