This simple stacking construction toy is easy to use and remarkably versatile. Remember how those log house construction sets fit together at their notched-out ends? Well, this design has a similar idea - only these pieces are grooved all the way down their length (rather than notched at the end). And once enough pieces have been fit together at right angles around two specific points, their "snap and lock" feature kicks in, which creates a very strong frame capable of supporting quite a bit of weight. There are seven different color-coded lengths of grooved stix, which make the projects in the idea books easy to follow at a glance.