Honestly, these can be marketed as something that toddlers can give to their daddies so they can watch us spend hour upon hour fascinated by these little stacking guys. My daughter (age 3.5) likes them inasmuch as she plays the Godzilla to my Tokyo. On the other hand, I, with my adult attention span, can spend hours trying different arrangements and patterns of stacking. probably the same gene responsible for my ability to watch Duel over and over and over again OK, the review... What are they? These are a collection of identically shaped 'robots' (painted wood cutouts) that have symmetrical notches in their bodies that allow other robots to hang, balance, and stack on each other. The fun comes in realizing the many, many different ways you can stack them. It takes imagination, fine motor skills, and - dare I say - finesse to explore the various combinations. For the budding engineer, they also provide nifty lessons in gravity, balance, and leverage, depending on how you stack them Pros: * They are attractive - These 'robots' are really identically shaped wooden cutouts painted in bright, vibrant colors to look like proper robots, with all the attendant dials and gauges you would expect to see on a robot. The colors are bright and cheerful. * They are durable - After many, many encounters with my resident Godzilla, these little stacking guys have not only held up, they still look almost new. One nice aspect to this toy is that the paint job can really take a beating without it affecting functionality in the least. * They stimulate imagination and hand-eye coordination - Well, they do for this daddy, anyhow, unless you count the way a toddler will finely calculate the force necessary to do maximum damage as she stomps through my work. Joking aside, it seems to me that these would have a similar effect that puzzles do. Indeed, I enjoy watching my daughter turn these around to see how each notch will hold up the robot as it is placed on another. That is, when I allow her to play with them after my turn. Really, the beauty of these is that they stimulate the brain without the need for bells, whistles, or batteries. * No batteries, No noise, Nothing to break or wear out - Unlike some other toys that eat batteries, or make terrifying noises in the middle of the night when they are supposed to be off (like the toy phone that ultimately met an untimely demise in my workshop one weekend) these stacking robots are simple and straightforward. I suppose they could break, but you'd have to beat one with a hammer to find out. * Value - While I do think that the cost is reasonable to begin with, I also think that this ranks huge in the value department. There aren't many toys in our home that deliver the bang for the buck that this one has. Cons: * Age appropriate? I'm not exactly sure when my daughter will be more interested in building things than tearing things down, so it's a good thing these are tough toys. If you want the immediate gratification that comes with watching your child spend hours with his or her new toy right away, check to see where they are on the development curve. Or, if you are like me, get them these stacking robots early and enjoy watching that devilish glint appear in their eye as you begin to build your tower... Other Thoughts: These appeal to this reviewer primarily because they stimulate the mind without gadgetry. I'm no Luddite, mind you, but I do appreciate a break from the electronics sometimes. I appreciate their durability. I really, really like the fact that both daughter and daddy can enjoy this toy both together and independently. Fun, educational, durable, and inexpensive... and an easy five stars!