It may be that block toys are a relatively good way for kids, say, 1-8, to learn about shapes, fitting, balance, etc.But I would suggest that usually it would be better for the blocks (1) to have different sizes and (2) all the dimensions, length, width, and height, with ratios 1, 2, 3, and at most 4. Mostly the shapes should be just rectangular parallelepipids but with maybe some arcs or circles thrown in. Then, say, build a bridge with the longest span or a tower of greatest height — no glue or fasteners permitted! Pictures on the blocks are from irrelevant down to distractions. The blocks I had had prints of railroad cars on the sides, but I never regarded the blocks as having anything to do with railroads, and soon the printing wore off!