These get used a lot in out house. I love that they are not overly high and can be rearranged. We use these on a really big tumble mat (the type you'd use for gymnastics). I first started my search for these after I took my baby to Gymboree classes and noticed how much she loved to climb . Instead of telling her no she can't climb in the house I'm the type of mom that would prefer to provide her with a place she can climb. She got these when she was 6 or 8 months old and she's still using them like crazy at 2 yros. The angled ones can even be used to prop the kids up when reading a book, watching tv, or what ever else you can think of. I haven't had any rips or tears with these, they're made of sturdy flexible material. The bottoms of each piece has a gripper type material to prevent it from sliding when stacked on top of another block. That was actually my question when I bought this set.