Some infant-development toys (formerly just known as "toys") are classics that need no updating, modernizing or retooling. Take the standard set of baby toy blocks. The last time they were significantly altered to "keep up with the times" was when they replaced cave stones as the preferred stacking medium in childhood.
While it appears that your infant is "just" banging blocks together or making a small pile, there's a lot going on in the way of development. Playing with blocks helps your infant learn shapes, the concept of counting -- and even fractions -- as they match up one single block with two halves of a similarly sized block.
There is also a fun lesson to be learned about gravity, and your baby will be eager to repeat experimental test results by repeatedly dropping blocks, picking them up and dropping them again. Your infant will also start to learn balancing skills as he or she picks up, holds or transports a block using only one hand.
These early experiments with blocks will pave the way toward later understanding about making rows, identifying and grouping same-shaped or same-colored blocks and building more complicated structures.