Refillable Discovery BlocksTransform everyday block play into a hands on learning adventure with the 8 Piece Discovery Windows Fillable Wooden Blocks Set. These innovative hardwood framed blocks feature clear acrylic windows that allow children to explore objects, textures, and natural materials in an interactive and meaningful way. Each block measures 4 inches square and 1. 75 inches deep, making them the perfect size for little hands. The removable wooden ends make it easy