Plus-Plus is a whole new class of construction toy! One simple shape contains endless possibilities and hours of fun. Each piece easily connects to the next and lets your imagination create colorful flat mosaics or work in 3-D to make more intricate builds. Even curves are possible thanks to the unique design of this deceptively simple shape! A perfect STEM toy to develop fine motor skills, focus and patience - as well as design, imagination and creativity! All Plus-Plus sets are compatible with each other and this open play set adds more pieces and colors to the collection for more possibilities and fun. Details: Assorted basic colors Various sized blocks 3,600 pieces Includes a reusable storage tub Includes idea guide booklet BPA-free and phthalate-free