Wooden blocks, foam blocks and wooden shapes with the trays are all a FAVORITE of every grade level. I'm fortunate to have most of these at all four schools. My students use them when they finish early on a project. They ask me before they get them out and I know that sounds like an interruption but it's better than if I announce at the beginning of each class "You can use the blocks if you finish early". Then they all would hurry just to get to the blocks. I usually have a day or two per year where we spend the entire art session just using and creating with the blocks.