Block play may not result in castles and towers at this stage, but exploring blocks are still purposeful to them! 

Infants learn to Explore the physical properties of the blocks while increasing and strengthening eye hand coordination and fine motor control. 

When building towers, infants explore the concept of gravity, cause and effect. You can also play peek a boo with your blocks! 

Block play may look like this: 

• Manipulate/feel blocks with hands
• Put blocks in mouth
• Reach for blocks
• Drop blocks repeatedly, especially if in a high chair
• Knock down a stack of blocks
• Older infants (approximately 8-12 months) will look for a hidden block

I really love these sensory blocks I found at Walmart for its texture. But you can use pretty much anything to create the same block play experience such as boxes, tubes, foam blocks, wooden blocks etc.