I stumbled upon this great toy as I was searching for gift ideas for a birthday present. Traditional block set + precision cut = endless opened ended possibilities = FUN!!! These blocks can be stacked just like traditional blocks, but there's more ... with the hollowed out middle, it adds a whole new dimension to "just" blocks. These are blocks and tinker toys combined!! What kids wouldn't want to receive these? These fit my criteria for great gifts - sustainably-harvested woods, non-toxic coloring and recycled packaging.