When I got my nephew one of the smaller sets for his third birthday, he really enjoyed the way these crazy blocks would stick together or repel eachother as if by magic. Since the smaller set was such a success, I thought I'd go big this Christmas (especially when Amazon had their gold box sale, offering the 42 block set for around $60). When I opened the set to repack the blocks since they're traveling this Christmas, I was dusappointed to discover that Tegu has basically sabotaged their own product's potential as a building toy. Let me explain. The best blocks in any tegu set are the small 1x1x1 cubes. These cubes have a magnet in every surface, which makes it possible to stick them (and other pieces) together in interesting ways. The next best are the flat 1x2 planks, which have only two magnets, but since these pieces are so thin, you have four potential sticking points, two on the front two on the back. Had Tegu continued this pattern for all of their pieces, I would have no complaints. Unfortunately, the larger the pieces grow, the fewer magnetic sticking points you will find in each one. The large, flat 1x7 planks have only three magnetic points, one at each end and one in the middle. If you planned on adding plank walls, a second story floor, or a roof to your structure, think again. The blocks' design makes it impossible to build anything with consecutively laid out planks. The trapezoidal blocks that seem to promose the potential for peaked roofs or angles for your structure have only two magnets, and both of those are in the angles surfaces. Because the block has no magnets in the top or bottom, it's impossible to brace, and the magnets arenxt strong enough to hold together any sort of peak on their own. Worse, because those magnets are of opposing polarity, instead of both being negative or positive, angled structures that connect back to the main body usually end up refusing to attach on one side. The only interesting thing you can build with them is the four-part square shown on the box. The absolute worst pieces in the box, however, are the tall 1x1x8 pieces that tegu uses to mock up skeleton houses on the cover illustration. These pieces have a total of two magnets which gives you only two sticking points, one on either end of the block. This, combined with their great weight, means that they can, practically speaking, *only* be used as vertical pillars; but thanks to their great height and lack of any magnetic sticking points on the sides, these pilars are impossible to brace or build out from, so you can only build extremely flimsy empty box frames as shown on the cover. It's not what I'd call a design full of possibilities. I don't mean to rag on Tegu. Sets using mostly smaller blocks can be very compelling and fun to play with. However, any set with blocks and planks larger than 3" ends up feeling cheap and difficult to work with. I understand that the magnets are probably the most expensive component in each block, and that Tegu runs a very worthy work program; but if they want to bill these magnetic blocks as a constructor toy, they should offer large block designs that don't actively hinder construction (i.e. that have a few more sticking points), or else stick to making smaller blocks. It would be a simple fix, and not an expensive one for the plank pieces (since each magnet provides two sticking points, meaning that a 1x6 plank would have the same number of magnets as the little cubes that they have not trouble manufacturong profitably). They could also increase the blocks' potential as a stem toy simply and inexpensively by marking each magnet with either a + or a -- sign depending on its polarity. This would give kids a simple visual marker to show that positive and negative sides stick together, rather than using trial and error, flipping each block until it fits. Tegu already prints its name on each of the blocks, so printing or burning a small polarity sign won't add much, if anything to the cost of the bricks. TL;DR: The small Tegu blocks are great, but the larger pieces are practically useless due to their small number of magnets (some of the largest pieces have 1/3 the magnets found in their smallest cubes). This makes Tegu a poor construction toy, especially compared to something as versitile as Legos. If you buy Tegu, buy a smaller set. Big pieces are more frustrating than fun, and more irritating to incorporate into your structure than useful.