Pastel Sensory Blocks by PlanToysPastel sensory blocks by PlanToys. This set of 6 sensory blocks consists of 2 visual blocks, 2 auditory blocks and 2 texture blocks in soft pastels and natural wood. Storage bag included. Each block is 3. 5cm square. Made from natural rubber wood trees that no longer produce latex. To keep the wood pure, no fertilizer is added to the soil three years prior to cut the trees down. To strengthen the wood, PlanToys uses a chemical free kiln drying